arch: aarch32: place .bss, .noinit sections at the end of the binary

This is a follow up to #53262, which still lacked the adjustment of the
.noinit section's position within the binary by the time the PR went
stale.

Adjust the linker command file so that the .bss and .noinit sections
are placed at the end of the resulting binary. Until now, those sections
have been located somewhere in the middle of the binary, so that the
inclusion of structures like statically defined heaps or large zero-
initialized arrays reflected 1:1 in the resulting binary's size. Even
for a stripped binary, such data was included in full as the linker
couldn't omit it due to subsequent sections within the binary.

This fix has been tested with a 32 MB statically allocated heap and
a 32 MB uint8 zero-initialized array. Both structures are clearly
identifyable in the memory consumption statistics, however, the final
binary's size is unaffected by their inclusion.

Signed-off-by: Immo Birnbaum <mail@birnbaum.immo>