qeth: Remove usage of subsys.rwsem

the current driver tree contains the removal of subsys.rwsem.
Unfortunately, this breaks qeth. However, it should be no problem to
fix the walking of the devices for /proc/qeth:

No need to take subsys.rwsem during walking the devices,
driver_find_devices() should already suffice.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/s390/net/qeth_proc.c

@@ -37,7 +37,6 @@ qeth_procfile_seq_start(struct seq_file *s, loff_t *offset)
 	struct device *dev = NULL;
 	loff_t nr = 0;
 
-	down_read(&qeth_ccwgroup_driver.driver.bus->subsys.rwsem);
 	if (*offset == 0)
 		return SEQ_START_TOKEN;
 	while (1) {
@@ -53,7 +52,6 @@ qeth_procfile_seq_start(struct seq_file *s, loff_t *offset)
 static void
 qeth_procfile_seq_stop(struct seq_file *s, void* it)
 {
-	up_read(&qeth_ccwgroup_driver.driver.bus->subsys.rwsem);
 }
 
 static void *