net/mlx5: Annotate mutex destroy for root ns

Invoke mutex_destroy() to catch any errors.

Fixes: 2cc43b49 ("net/mlx5_core: Managing root flow table")
Signed-off-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

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

@@ -2350,6 +2350,12 @@ static int init_root_tree(struct mlx5_flow_steering *steering,
 
 static void del_sw_root_ns(struct fs_node *node)
 {
+	struct mlx5_flow_root_namespace *root_ns;
+	struct mlx5_flow_namespace *ns;
+
+	fs_get_obj(ns, node);
+	root_ns = container_of(ns, struct mlx5_flow_root_namespace, ns);
+	mutex_destroy(&root_ns->chain_lock);
 	kfree(node);
 }