x86: Clean up mem*io functions.

Iomem has no special significance on x86.  Use the standard mem*
functions instead of trying to call other versions.  Some fixups
are needed to match the function prototypes.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1265380629-3212-6-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>