net/mlx5: E-Switch, Split VF and special vports for offloads mode

When driver is entering offloads mode, there are two major tasks to
do: initialize flow steering and create representors. Flow steering
should make sure enough flow table/group spaces are reserved for all
reps. Representors will be created in a group, all or none.

With the introduction of ECPF, flow steering should still reserve the
same spaces. But, the representors are not always loaded/unloaded in a
single piece. Once ECPF is in offloads mode, it will get the number
of VF changing event from host PF. In such scenario, only the VF reps
should be loaded/unloaded, not the reps for special vports (such as
the uplink vport).

Thus, when entering offloads mode, driver should specify the total
number of reps, and the number of VF reps separately. When leaving
offloads mode, the cleanup should use the information self-contained
in eswitch such as number of VFs.

This patch doesn't change any functionality.

Signed-off-by: Bodong Wang <bodong@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>