Optimize the ordering of sections in RW_DATA_SECTION.

The old RW_DATA_SECTION had INIT_TASK_DATA (which was
more-than-PAGE_SIZE-aligned), followed by a bunch of small alignment
stuff, followed by more PAGE_SIZE-aligned stuff, so you wasted memory
in the middle of .data re-aligning back up to PAGE_SIZE.

This patch sorts the sections by alignment requirements, which should
pack them essentially optimally.

Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>