[S390] css: Use css_device_id for bus matching.

css_device_id exists, so use it for determining the right driver
(and add a match_flags which is always 1 for valid types).

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>