[PATCH] s390: ccwgroup online attribute

Make the interface for setting ccw group devices on-/offline consistent with
that for ccw devices: Check if the device driver provided a set_{on,off}line
function and just set the device on-/offline if not.

Signed-off-by: Cornelia Huck <cohuck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>