net: net_failover: fix typo in net_failover_slave_register()

Sync both unicast and multicast lists instead of unicast twice.

Fixes: cfc80d9a ("net: Introduce net_failover driver")
Reviewed-by: NJoao Martins <joao.m.martins@oracle.com>
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/net_failover.c

@@ -527,7 +527,7 @@ static int net_failover_slave_register(struct net_device *slave_dev,
 
 	netif_addr_lock_bh(failover_dev);
 	dev_uc_sync_multiple(slave_dev, failover_dev);
-	dev_uc_sync_multiple(slave_dev, failover_dev);
+	dev_mc_sync_multiple(slave_dev, failover_dev);
 	netif_addr_unlock_bh(failover_dev);
 
 	err = vlan_vids_add_by_dev(slave_dev, failover_dev);