[S390] struct device - replace bus_id with dev_name(), dev_set_name()

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>