s390/qeth: don't init refcount twice for mcast IPs

mcast IP objects are allocated within qeth_l3_add_mcast_rtnl(),
with .ref_counter already set to 1 via qeth_l3_init_ipaddr().
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_l3_main.c

@@ -1235,7 +1235,6 @@ static void qeth_l3_rx_mode_work(struct work_struct *work)
 					kfree(addr);
 					break;
 				}
-				addr->ref_counter = 1;
 				fallthrough;
 			default:
 				/* for next call to set_rx_mode(): */