net/mlx5: E-Switch, Reorganize and rename fdb flow tables

We have several fdb flow tables for each of the legacy and switchdev
modes. In the switchdev mode, there are fast path and slow path flow
tables. Towards adding more flow tables in upcoming patches, reorganize
and rename the various existing ones to reflect their functionality.

Signed-off-by: Chris Mi <chrism@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>