net/mlx5: LAG, block multiport eswitch LAG in case ldev have more than 2 ports

multiport eswitch LAG is not supported over more than two ports. Add a check in
order to block multiport eswitch LAG over such devices.
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/lag/mpesw.c

@@ -65,6 +65,7 @@ static int mlx5_mpesw_metadata_set(struct mlx5_lag *ldev)
 	return err;
 }
 
+#define MLX5_LAG_MPESW_OFFLOADS_SUPPORTED_PORTS 2
 static int enable_mpesw(struct mlx5_lag *ldev)
 {
 	struct mlx5_core_dev *dev0 = ldev->pf[MLX5_LAG_P1].dev;
@@ -74,6 +75,9 @@ static int enable_mpesw(struct mlx5_lag *ldev)
 	if (ldev->mode != MLX5_LAG_MODE_NONE)
 		return -EINVAL;
 
+	if (ldev->ports > MLX5_LAG_MPESW_OFFLOADS_SUPPORTED_PORTS)
+		return -EOPNOTSUPP;
+
 	if (mlx5_eswitch_mode(dev0) != MLX5_ESWITCH_OFFLOADS ||
 	    !MLX5_CAP_PORT_SELECTION(dev0, port_select_flow_table) ||
 	    !MLX5_CAP_GEN(dev0, create_lag_when_not_master_up) ||