From: Arnd Bergmann <arnd@arndb.de>

On s390, kmem_bufctl_t was added inside of an #ifdef, breaking
64 bit builds.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>