bridge: call NETDEV_JOIN notifiers when add a slave

In the previous patch I added NETDEV_JOIN, now
we can notify netconsole when adding a device to a bridge too.

Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Neil Horman <nhorman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -338,6 +338,8 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 	if (IS_ERR(p))
 		return PTR_ERR(p);
 
+	call_netdevice_notifiers(NETDEV_JOIN, dev);
+
 	err = dev_set_promiscuity(dev, 1);
 	if (err)
 		goto put_back;