ser_gigaset: return -ENOMEM on error instead of success

If we can't allocate the resources in gigaset_initdriver() then we
should return -ENOMEM instead of zero.

Fixes: 2869b23e4b95 ("[PATCH] drivers/isdn/gigaset: new M101 driver (v2)")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/gigaset/ser-gigaset.c b/drivers/isdn/gigaset/ser-gigaset.c
index d1f8ab9..b90776e 100644
--- a/drivers/isdn/gigaset/ser-gigaset.c
+++ b/drivers/isdn/gigaset/ser-gigaset.c
@@ -755,8 +755,10 @@
 	driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
 				    GIGASET_MODULENAME, GIGASET_DEVNAME,
 				    &ops, THIS_MODULE);
-	if (!driver)
+	if (!driver) {
+		rc = -ENOMEM;
 		goto error;
+	}
 
 	rc = tty_register_ldisc(N_GIGASET_M101, &gigaset_ldisc);
 	if (rc != 0) {