net/mlx5e: allow TSO on VXLAN over VLAN topologies

since mlx5 hardware can segment correctly TSO packets on VXLAN over VLAN
topologies, CPU usage can improve significantly if we enable tunnel
offloads in dev->vlan_features, like it was done in the past with other
NIC drivers (e.g. mlx4, be2net and ixgbe).
Signed-off-by: NDavide Caratti <dcaratti@redhat.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -4878,6 +4878,8 @@ static void mlx5e_build_nic_netdev(struct net_device *netdev)
 		netdev->hw_enc_features |= NETIF_F_GSO_UDP_TUNNEL |
 					   NETIF_F_GSO_UDP_TUNNEL_CSUM;
 		netdev->gso_partial_features = NETIF_F_GSO_UDP_TUNNEL_CSUM;
+		netdev->vlan_features |= NETIF_F_GSO_UDP_TUNNEL |
+					 NETIF_F_GSO_UDP_TUNNEL_CSUM;
 	}
 
 	if (mlx5e_tunnel_proto_supported(mdev, IPPROTO_GRE)) {