net/mlx5: remove redundant check for hairpin queue

net/mlx5: remove redundant check for hairpin queue

The mlx5_rxq_is_hairpin() function checks whether RxQ type is Hairpin.
It is done by reading a flag in Rx control structure coming from
mlx5_rxq_ctrl_get() function.

The function verifies that the queue index is valid even though it has
been checked within the mlx5_rxq_ctrl_get() function.

This patch removes the redundant check.

Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>