spidev warning fix

Git rid of "warning: passing arg 2 of `access_ok' makes pointer from integer
without a cast" reported on SH ...  most architectures use macros in that
test, SH uses inlined functions.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>