arch: arc: Kconfig: Remove redundant 'default n' properties

Bool symbols implicitly default to 'n'.

A 'default n' can make sense e.g. in a Kconfig.defconfig file, if you
want to override a 'default y' on the base definition of the symbol. It
isn't used like that on any of these symbols though.

Also fix the 'default' on XIP. Due to Zephyr's prefer-later-defaults
behavior, it was always set to 'y' (when the dependencies were
satisfied).

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>

arch/arc/Kconfig

@@ -126,8 +126,7 @@ config	FAULT_DUMP
 	  0: Off.
 
 config	XIP
-	default n if UART_NSIM
-	default y
+	default y if !UART_NSIM
 
 config GEN_ISR_TABLES
 	default y
@@ -138,22 +137,19 @@ config GEN_IRQ_START_VECTOR
 config HARVARD
 	prompt "Harvard Architecture"
 	bool
-	default n
 	help
 	  The ARC CPU can be configured to have two busses;
 	  one for instruction fetching and another that serves as a data bus.
 
 config CODE_DENSITY
 	prompt "Code Density Option"
 	bool
-	default n
 	help
 	  Enable code density option to get better code density
 
 config ARC_HAS_SECURE
 	bool
 	#  a hidden option
-	default n
 	help
 	  This option is enabled when ARC core supports secure mode
 
@@ -164,7 +160,6 @@ config ARC_MPU_ENABLE
 	bool "Enable MPU"
 	depends on CPU_HAS_MPU
 	select ARC_MPU
-	default n
 	help
 	  Enable MPU
 
@@ -175,7 +170,6 @@ endmenu
 config CACHE_LINE_SIZE_DETECT
 	bool
 	prompt "Detect d-cache line size at runtime"
-	default n
 	help
 	  This option enables querying the d-cache build register for finding
 	  the d-cache line size at the expense of taking more memory and code
@@ -195,11 +189,9 @@ config CACHE_LINE_SIZE
 
 config ARCH_CACHE_FLUSH_DETECT
 	bool
-	default n
 
 config CACHE_FLUSHING
 	bool
-	default n
 	prompt "Enable d-cache flushing mechanism"
 	help
 	  This links in the sys_cache_flush() function, which provides a

arch/arc/core/mpu/Kconfig

@@ -17,14 +17,12 @@ config ARC_MPU_VER
 config ARC_CORE_MPU
 	bool "ARC Core MPU functionalities"
 	depends on CPU_HAS_MPU
-	default n
 	help
 	  ARC core MPU functionalities
 
 config MPU_STACK_GUARD
 	bool "Thread Stack Guards"
 	depends on ARC_CORE_MPU && !ARC_STACK_CHECKING
-	default n
 	help
 	  Enable thread stack guards via MPU. ARC supports built-in stack protection.
 	  If your core supports that, it is preferred over MPU stack guard
@@ -35,6 +33,5 @@ config ARC_MPU
 	select ARC_CORE_MPU
 	select THREAD_STACK_INFO
 	select MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT if ARC_MPU_VER = 2
-	default n
 	help
 	  Target has ARC MPU (currently only works for EMSK 2.2/2.3 ARCEM7D)