[include][asm] add more FUNCTION and DATA macros for assembly
[arch][arm-m] move the initial stack over to the .prebss. section

The explicit initial stack section was unnecessary, since there was
already a more generic .bss.prebss. mechanism in the linker script.
[arch] further linker script cleanup

-added COMMON support
-remove SUBALIGN, which was being incorrectly used
-better align sections