sh: Use __INIT macro instead of .text.init.

The sh architecture has some code in the .text.init section, but it
does not reference that section in its linker scripts.

This change moves this code from the .text.init section to the
.init.text section, which is presumably where it belongs.

Signed-off-by: Tim Abbott <tabbott@mit.edu>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>