net/mlx5: Fix memory leak in cmd_exec()

If cmd_exec() is called with callback and mlx5_cmd_invoke() returns an
error, resources allocated in cmd_exec() will not be freed.

Fix the code to release the resources if mlx5_cmd_invoke() returns an
error.

Fixes: f086470 ("net/mlx5: cmdif, Return value improvements")
Reported-by: Alex Tereshkin <atereshkin@nvidia.com>
Signed-off-by: Chiara Meiohas <cmeiohas@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Vlad Dumitrescu <vdumitrescu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/1752753970-261832-2-git-send-email-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: chiarameiohas

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

@@ -1947,8 +1947,8 @@ static int cmd_exec(struct mlx5_core_dev *dev, void *in, int in_size, void *out,
 
 	err = mlx5_cmd_invoke(dev, inb, outb, out, out_size, callback, context,
 			      pages_queue, token, force_polling);
-	if (callback)
-		return err;
+	if (callback && !err)
+		return 0;
 
 	if (err > 0) /* Failed in FW, command didn't execute */
 		err = deliv_status_to_err(err);