net: ip: tcp: use zu format specifier for size_t

[cfriedt]

Describe the bug
Incorrect format specifiers cause warnings (escalated to errors in twister), breaking build.

To Reproduce
Steps to reproduce the behavior:

1. enable logging, debug logging
2. use twister to build something involving tcp
3. See error

Expected behavior
Successfull build

Impact
Showstopper for build (of gsoc-2022-thrift project)

Logs and console output

FAILED: zephyr/subsys/net/ip/CMakeFiles/subsys__net__ip.dir/tcp.c.obj 
ccache /Users/cfriedt/zephyr-sdk-0.15.0/aarch64-zephyr-elf/bin/aarch64-zephyr-elf-gcc -DKERNEL -DMBEDTLS_CONFIG_FILE=\"config-tls-generic.h\" -DTC_RUNID=0c07d0be06c2c78439c63428eea8ea72 -D_FORTIFY_SOURCE-
In file included from /Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/logging/log.h:11,
                 from /Users/cfriedt/Desktop/zephyrproject/zephyr/subsys/net/ip/tcp.c:7:
/Users/cfriedt/Desktop/zephyrproject/zephyr/subsys/net/ip/tcp.c: In function 'tcp_queue_recv_data':
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/net/net_core.h:47:35: error: format '%i' expects argument of type 'int', but argument 4 has type 'size_t' {aka 'long unsigned int'} [-Werror=form
   47 | #define NET_DBG(fmt, ...) LOG_DBG("(%s): " fmt,                         \
      |                                   ^~~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/logging/log_core.h:248:42: note: in definition of macro 'Z_LOG2'
  248 |                 z_log_printf_arg_checker(__VA_ARGS__); \
      |                                          ^~~~~~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/logging/log.h:71:25: note: in expansion of macro 'Z_LOG'
   71 | #define LOG_DBG(...)    Z_LOG(LOG_LEVEL_DBG, __VA_ARGS__)
      |                         ^~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/net/net_core.h:47:27: note: in expansion of macro 'LOG_DBG'
   47 | #define NET_DBG(fmt, ...) LOG_DBG("(%s): " fmt,                         \
      |                           ^~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/subsys/net/ip/tcp.c:1906:33: note: in expansion of macro 'NET_DBG'
 1906 |                                 NET_DBG("Adding at before queue, end_offset %i, pending_len %i",
      |                                 ^~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/net/net_core.h:47:35: error: format '%i' expects argument of type 'int', but argument 5 has type 'size_t' {aka 'long unsigned int'} [-Werror=form
   47 | #define NET_DBG(fmt, ...) LOG_DBG("(%s): " fmt,                         \
      |                                   ^~~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/logging/log_core.h:248:42: note: in definition of macro 'Z_LOG2'
  248 |                 z_log_printf_arg_checker(__VA_ARGS__); \
      |                                          ^~~~~~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/logging/log.h:71:25: note: in expansion of macro 'Z_LOG'
   71 | #define LOG_DBG(...)    Z_LOG(LOG_LEVEL_DBG, __VA_ARGS__)
      |                         ^~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/net/net_core.h:47:27: note: in expansion of macro 'LOG_DBG'
   47 | #define NET_DBG(fmt, ...) LOG_DBG("(%s): " fmt,                         \
      |                           ^~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/subsys/net/ip/tcp.c:1937:41: note: in expansion of macro 'NET_DBG'
 1937 |                                         NET_DBG("Adding at end of queue, start %i, end %i, len %i",
      |                                         ^~~~~~~
cc1: all warnings being treated as errors

ccache /Users/cfriedt/zephyr-sdk-0.15.0/aarch64-zephyr-elf/bin/aarch64-zephyr-elf-gcc -DKERNEL -DMBEDTLS_CONFIG_FILE=\"config-tls-generic.h\" -DTC_RUNID=40bf9f388de434f779657b8dbb125fc8 -D_FORTIFY_SOURCE/
In file included from /Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/logging/log.h:11,
                 from /Users/cfriedt/Desktop/zephyrproject/zephyr/subsys/net/ip/tcp.c:7:
/Users/cfriedt/Desktop/zephyrproject/zephyr/subsys/net/ip/tcp.c: In function 'tcp_queue_recv_data':
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/net/net_core.h:47:35: error: format '%i' expects argument of type 'int', but argument 5 has type 'size_t' {aka 'long unsigned int'} [-Werror=form
   47 | #define NET_DBG(fmt, ...) LOG_DBG("(%s): " fmt,                         \
      |                                   ^~~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/logging/log_core.h:248:42: note: in definition of macro 'Z_LOG2'
  248 |                 z_log_printf_arg_checker(__VA_ARGS__); \
      |                                          ^~~~~~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/logging/log.h:71:25: note: in expansion of macro 'Z_LOG'
   71 | #define LOG_DBG(...)    Z_LOG(LOG_LEVEL_DBG, __VA_ARGS__)
      |                         ^~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/include/zephyr/net/net_core.h:47:27: note: in expansion of macro 'LOG_DBG'
   47 | #define NET_DBG(fmt, ...) LOG_DBG("(%s): " fmt,                         \
      |                           ^~~~~~~
/Users/cfriedt/Desktop/zephyrproject/zephyr/subsys/net/ip/tcp.c:1937:41: note: in expansion of macro 'NET_DBG'
 1937 |                                         NET_DBG("Adding at end of queue, start %i, end %i, len %i",
      |                                         ^~~~~~~
cc1: all warnings being treated as errors
ninja: build stopped: subcommand failed.

Environment (please complete the following information):

• OS: macOS
• Toolchain: Zephyr SDK 0.15.0
• Commit: 356960b

Additional context
https://github.com/zephyrproject-rtos/gsoc-2022-thrift