net/mlx5: HWS, added definers handling

The Match Definer combines packet fields and a mask,
creating a key which can be used for packet matching
during steering flow processing.
This patch adds handling of definer objects in HWS.
Reviewed-by: Hamdan Agbariya <hamdani@nvidia.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>