net/mlx4_en: Add VXLAN ndo calls to the PF net device ops too

commit 9737c6ab upstream.

This is currently missing, which results in a crash when one attempts
to set VXLAN tunnel over the mlx4_en when acting as PF.

	[ 2408.785472] BUG: unable to handle kernel NULL pointer dereference at (null)
	[...]
	[ 2408.994104] Call Trace:
	[ 2408.996584]  [<ffffffffa021f7f5>] ? vxlan_get_rx_port+0xd6/0x103 [vxlan]
	[ 2409.003316]  [<ffffffffa021f71f>] ? vxlan_lowerdev_event+0xf2/0xf2 [vxlan]
	[ 2409.010225]  [<ffffffffa0630358>] mlx4_en_start_port+0x862/0x96a [mlx4_en]
	[ 2409.017132]  [<ffffffffa063070f>] mlx4_en_open+0x17f/0x1b8 [mlx4_en]

While here, make sure to invoke vxlan_get_rx_port() only when VXLAN
offloads are actually enabled and not when they are only supported.
Reported-by: Ido Shamay <idos@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ luis: backported to 3.16: used davem's backport to 3.17 ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

@@ -1724,7 +1724,7 @@ int mlx4_en_start_port(struct net_device *dev)
 	mlx4_set_stats_bitmap(mdev->dev, &priv->stats_bitmap);
 
 #ifdef CONFIG_MLX4_EN_VXLAN
-	if (priv->mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_VXLAN_OFFLOADS)
+	if (priv->mdev->dev->caps.tunnel_offload_mode == MLX4_TUNNEL_OFFLOAD_MODE_VXLAN)
 		vxlan_get_rx_port(dev);
 #endif
 	priv->port_up = true;
@@ -2434,6 +2434,10 @@ static const struct net_device_ops mlx4_netdev_ops_master = {
 	.ndo_rx_flow_steer	= mlx4_en_filter_rfs,
 #endif
 	.ndo_get_phys_port_id	= mlx4_en_get_phys_port_id,
+#ifdef CONFIG_MLX4_EN_VXLAN
+	.ndo_add_vxlan_port	= mlx4_en_add_vxlan_port,
+	.ndo_del_vxlan_port	= mlx4_en_del_vxlan_port,
+#endif
 };
 
 int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,