Creating a drop queue in mlx5 ends by creating a non polled queue, but if
the associated work queue could not be created the error was not handled
ending in a undefined situation.
Fixes: 2097d0d1e2cc ("net/mlx5: support basic flow items and actions") Cc: stable@dpdk.org Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>