net/mlx5: Query hca_cap_2 only when supported

On vport enable, where fw's hca caps are queried, the driver queries
hca_caps_2 without checking if fw truly supports them, causing a false
failure of vfs vport load and blocking SRIOV enablement on old devices
such as CX4 where hca_caps_2 support is missing.

Thus, add a check for the said caps support before accessing them.

Fixes: e5b9642a ("net/mlx5: E-Switch, Implement devlink port function cmds to control migratable")
Signed-off-by: Maher Sanalla <msanalla@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

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

@@ -807,6 +807,9 @@ static int mlx5_esw_vport_caps_get(struct mlx5_eswitch *esw, struct mlx5_vport *
 	hca_caps = MLX5_ADDR_OF(query_hca_cap_out, query_ctx, capability);
 	vport->info.roce_enabled = MLX5_GET(cmd_hca_cap, hca_caps, roce);
 
+	if (!MLX5_CAP_GEN_MAX(esw->dev, hca_cap_2))
+		goto out_free;
+
 	memset(query_ctx, 0, query_out_sz);
 	err = mlx5_vport_get_other_func_cap(esw->dev, vport->vport, query_ctx,
 					    MLX5_CAP_GENERAL_2);