x86: kmmio.c: Add and use pr_fmt(fmt)

- Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 - Strip "kmmio: " from pr_<level>s

Signed-off-by: Joe Perches <joe@perches.com>
LKML-Reference: <7aa509f8a23933036d39f54bd51e9acc52068049.1260383912.git.joe@perches.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>