arm: cortex_a_r linker: move data section between rodata and bss

By moving data section between rodata and bss, and disabling
Kconfig LINKER_LAST_SECTION_ID by default if non-XIP (it is
seems only needed for XIP), the size of zephyr.bin can be
reduced significantly on non-XIP system.

As a result, moving __kernel_ram_start to another place
to ensure it still include bss + data as before.

Signed-off-by: Dat Nguyen Duy <dat.nguyenduy@nxp.com>