net/mlx5: optimize queue type checks

net/mlx5: optimize queue type checks

The RxQ/TxQ control structure has a field named type. This type is enum
with values for standard and hairpin.
The use of this field is to check whether the queue is of the hairpin
type or standard.

This patch replaces it with a boolean variable that saves whether it is
a hairpin.

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