net/mlx5: Use PTR_ERR_OR_ZERO rather than its implementation

PTR_ERR_OR_ZERO contains if(IS_ERR(...)) + PTR_ERR. It is better
to use it directly. hence just replace it.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>