arch/tile: minor whitespace/naming changes for string support files

Our internal process shares memcpy, memset, etc., with libc, and
we did some minor tweaking as part of moving from uclibc to glibc,
which is now reflected in the kernel versions of these files.

There are no semantic changes in this commit, just whitespace
(memcpy_32.S now properly uses tabs), naming (memmove.c instead
of memmove_32.c, since TILE-Gx shares the file with TILEPro),
and a couple of other minor tweaks.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>