net/mlx5e: Refactor mlx5e flow steering structs

Slightly refactor and re-order the flow steering structs,
tables and data-bases for better self-containment and
flexibility to add more future steering phases
(tables/rules/data bases) e.g: aRFS.

Changes:
1. Move the vlan DB and address DB into their table structs.
2. Rename steering table structs to unique format: mlx5e_*_table,
e.g: mlx5e_vlan_table.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>