There's nothing arch-specific about check_signature(), so move it to
<linux/io.h>.  Use a cross between the Alpha and i386 implementations as
the generic one.
Signed-off-by: NMatthew Wilcox <willy@parisc-linux.org>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>