net/mlx5e: free page before return

Instead of directly return, goto the error handling label to free
allocated page.

Fixes: 5f29458b ("net/mlx5e: Support dump callback in TX reporter")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>