arch: arm: cortex_m: Consolidate bss/noinit sections for kernel/user mode

Userspace originally required bss to precede kobject_data, as
kobject_data size was not known until the final linking stage (#21747).

#33687 reserved space for kobject_data, allowing bss to now be after
kobject_data.

Placing bss/noinit at the end of the linker script reduces the size
of a "zephyr.bin" file, as the NOLOAD sections can be excluded. It
also keeps the code common between kernel/user mode

Signed-off-by: Grant Ramsay <gramsay@enphaseenergy.com>