sh: Kill off udivdi3 div64_32 wrapping.

Previously we've been handling udivdi3 references and wrapping
them in to div64_32() automatically. This doesn't get a lot of
use, however, and as akpm noted in the recent thread on l-k:

	http://lkml.org/lkml/2007/2/27/241



we're better off simply ripping it out and going the do_div()
route if there happen to be any places that need it.

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