i386: Fix broken mmiocfg accesses

Commit 3320ad99 broke mmio config space
accesses totally on i386 - it dropped the "reg" offset to the address.

Cc: dean gaudet <dean@arctic.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>