net/mlx5: DR, Remove hw_ste from mlx5dr_ste to reduce memory

It can be calculated via function mlx5dr_ste_get_hw_ste().
Very simple and lightweight, no need to use a dedicated member.

Reduce 8 bytes from struct mlx5dr_ste and its size is 48 bytes now.

Signed-off-by: Rongwei Liu <rongweil@nvidia.com>
Reviewed-by: Shun Hao <shunh@nvidia.com>
Reviewed-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>