net/mlx5e: TC, fix missing error code

Missing error code when mlx5e_tc_act_stats_create fails

Fixes: d13674b1 ("net/mlx5e: TC, map tc action cookie to a hw counter")
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Oz Shlomo <ozsh@nvidia.com>
Reviewed-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>