drivers/net/wireless/b43/main.c needs io.h

m68k:

drivers/net/wireless/b43/main.c:251: error: implicit declaration of function 'mmiowb'

Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>