net/mlx5: E-switch, Prepare eswitch to handle SF vport

Prepare eswitch to handle SF vport during
(a) querying eswitch functions
(b) egress ACL creation
(c) account for SF vports in total vports calculation

Assign a dedicated placeholder for SFs vports and their representors.
They are placed after VFs vports and before ECPF vports as below:
[PF,VF0,...,VFn,SF0,...SFm,ECPF,UPLINK].

Change functions to map SF's vport numbers to indices when
accessing the vports or representors arrays, and vice versa.

Signed-off-by: Vu Pham <vuhuong@nvidia.com>
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>