net/mlx5e: Add devlink hairpin queues parameters

net/mlx5e: Add devlink hairpin queues parameters

We refer to a TC NIC rule that involves forwarding as "hairpin".
Hairpin queues are mlx5 hardware specific implementation for hardware
forwarding of such packets.

Per the discussion in [1], move the hairpin queues control (number and
size) from debugfs to devlink.

Expose two devlink params:
- hairpin_num_queues: control the number of hairpin queues
- hairpin_queue_size: control the size (in packets) of the hairpin queues

[1] https://lore.kernel.org/all/20230111194608.7f15b9a1@kernel.org/

Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20230314054234.267365-12-saeed@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>