macvlan: fix panic if lowerdev in a bond

commit a35e2c1b (macvlan: use rx_handler_data pointer to store
macvlan_port pointer V2) added a bug in macvlan_port_create()

Steps to reproduce the bug:

# ifenslave bond0 eth0 eth1

# ip link add link eth0 up name eth0#1 type macvlan
->error EBUSY

# ip link add link eth0 up name eth0#1 type macvlan
->panic


Fix: Dont set IFF_MACVLAN_PORT in error case.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/macvlan.c

@@ -585,8 +585,8 @@ static int macvlan_port_create(struct net_device *dev)
 	err = netdev_rx_handler_register(dev, macvlan_handle_frame, port);
 	if (err)
 		kfree(port);
-
-	dev->priv_flags |= IFF_MACVLAN_PORT;
+	else
+		dev->priv_flags |= IFF_MACVLAN_PORT;
 	return err;
 }