net/mlx5e: Use dedicated uplink vport netdev representor

Currently, when running in sriov switchdev mode, we are using the PF
netdevice as the uplink representor, this is problematic from few aspects:

- will break when the PF isn't eswitch manager (e.g smart NIC env)
- misalignment with other NIC switchdev drivers
- makes us have and maintain special code, hurts the driver quality/robustness
- which in turn opens the door for future bugs

As of each and all of the above, we move to have a dedicated netdev representor
for the uplink vport in a similar manner done for for the VF vports.

This includes the following:

1. have an uplink rep netdev as we have for VF reps
2. all reps use same load/unload functions
3. HW stats for uplink based on physical port counters and not vport counters
4. link state for the uplink managed through PAOS and not vport state
5. the uplink rep has sysfs link to the PF PCI function && uses the PF MAC address

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