net/mlx5: DR, Create multi-destination table for SW-steering use

Currently SW steering doesn't have the means to access HW iterators to
support multi-destination (FTEs) flow table entries.

In order to support multi-destination FTEs for port-mirroring, SW
steering will create a dedicated multi-destination FW managed flow table
and FTEs via direct FW commands that we introduced in the previous patch.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>