sh: Migrate necessary libgcc bits in to arch/sh/lib for SUPERH32.

This moves in the necessary libgcc bits for SUPERH32 and drops the
libgcc linking for the regular targets. This in turn allows us to rip
out quite a few hacks both in sh_ksyms_32 and arch/sh/Makefile.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>