net/mlx5: HWS, added debug dump and internal headers

Added debug dump of the existing HWS state,
and all the required internal definitions.

To dump the HWS state, cat the following debugfs node:

  cat /sys/kernel/debug/mlx5/<PCI>/steering/fdb/ctx_<ctx_id>

Reviewed-by: Hamdan Agbariya <hamdani@nvidia.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>