net/mlx5: Avoid forwarding to other eswitch uplink

Do not allow forwarding of encapsulated traffic received from one eswtich's
uplink to another eswtich's uplink.
Signed-off-by: Eli Cohen <eli@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c

@@ -66,6 +66,9 @@ static int get_route_and_out_devs(struct mlx5e_priv *priv,
 	      mlx5e_is_uplink_rep(netdev_priv(*out_dev))))
 		return -EOPNOTSUPP;
 
+	if (mlx5e_eswitch_uplink_rep(priv->netdev) && *out_dev != priv->netdev)
+		return -EOPNOTSUPP;
+
 	return 0;
 }