common/mlx5: fix freeing on flex parser creation failure

common/mlx5: fix freeing on flex parser creation failure

The mlx5_devx_cmd_create_flex_parser function defines a local array
(with constant size) named in, and then allocates a pointer to
mlx5_devx_obj structure by the mlx5_malloc function.

If the allocation fails, the function releases the array in and returns
NULL. However, the array has been defined locally on the stack and the
mlx5_free function is not required to release it.

Remove the call to the mlx5_free function.

Fixes: 66914d19d135 ("common/mlx5: convert control path memory to unified malloc")
Cc: stable@dpdk.org
Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>