net/mlx5e: Cleanup Flow Steering level

Flow Steering levels are used to determine the order between the tables.
As of today, each one of these tables follows the TTC table, and hijacks
its traffic, and cannot be combined together for now. Putting them in
the same layer better reflects the situation.

Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>