RTEMS.cmake: add quotes around ${RTEMS_BSP_C_FLAGS}.

[Jkillelea]

Without the quotes, only the first argument is actually passed to the compiler by rtems-syms.

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution
A clear and concise description of what the contribution is.

• This change ensures that all flags from RTEMS_BSP_C_FLAGS are passed from rtems-syms to the compiler.

Testing performed
Steps taken to test the contribution:

1. Only tested to check if compilation succeeds.

Expected behavior changes
A clear and concise description of how this contribution will change behavior and level of impact.

• API Change: N/A
• Behavior Change: xxx (if applicable)

Before: The only flag that rtems-syms passes to the compiler is -march=armv7-a. This causes a crash because the compiler assumes the wrong floating point ABI.

/home/jacob/projects/rtems/6/bin/rtems-syms -vvv -e -c -march=armv7-a -mthumb -mfpu=neon -mfloat-abi=hard -mtune=cortex-a7 -fno-common -fdata-sections -ffunction-sections -C /home/jacob/projects/rtems/6/bin/arm-rtems6-gcc -o cmTC_56657.exe-dl-sym.o cmTC_56657.exe-prelink
    RTEMS Kernel Symbols 6.ac1fee4f04fe
    kernel: cmTC_56657.exe-prelink
    cache:load-sym: object files: 1
    cache:load-sym: symbols: 1459
    Filtered symbols: 1074
    symbol C file: /tmp/ccaneeaa.c
    symbol O file: cmTC_56657.exe-dl-sym.o
    execute: /home/jacob/projects/rtems/6/bin/arm-rtems6-gcc -march=armv7-a -O2 -c -o cmTC_56657.exe-dl-sym.o /tmp/ccaneeaa.c 

After: All flags are correctly passed to the compiler. The floating point ABI is correctly specified.

/home/jacob/projects/rtems/6/bin/rtems-syms -vvv -e -c "-march=armv7-a -mthumb -mfpu=neon -mfloat-abi=hard -mtune=cortex-a7 -fno-common -fdata-sections -ffunction-sections" -C /home/jacob/projects/rtems/6/bin/arm-rtems6-gcc -o cmTC_ed3ae.exe-dl-sym.o cmTC_ed3ae.exe-prelink
RTEMS Kernel Symbols 6.ac1fee4f04fe
kernel: cmTC_ed3ae.exe-prelink
cache:load-sym: object files: 1
cache:load-sym: symbols: 1463
Filtered symbols: 1075
symbol C file: /tmp/ccNoeeaa.c
symbol O file: cmTC_ed3ae.exe-dl-sym.o
execute: /home/jacob/projects/rtems/6/bin/arm-rtems6-gcc -march=armv7-a -mthumb -mfpu=neon -mfloat-abi=hard -mtune=cortex-a7 -fno-common -fdata-sections -ffunction-sections -O2 -c -o cmTC_ed3ae.exe-dl-sym.o /tmp/ccNoeeaa.c 

System(s) tested on

• Hardware: Raspberry Pi 3.
• OS: Building on Ubuntu 22.04 for RTEMS 6.
• Versions: PSP draco-rc4.

Additional context
N/A

Third party code
N/A

Contributor Info - All information REQUIRED for consideration of pull request
Full name and company/organization/center of all contributors ("Personal" if individual work)

• Jacob Killelea / Personal