net/mlx5e: Register devlink ports for physical link, PCI PF, VFs

Register devlink port of physical port, PCI PF and PCI VF flavour
for each PF, VF when a given devlink instance is in switchdev mode.

Implement ndo_get_devlink_port callback API to make use of registered
devlink ports.
This eliminates ndo_get_phys_port_name() and ndo_get_port_parent_id()
callbacks. Hence, remove them.

An example output with 2 VFs, without a PF and single uplink port is
below.

$devlink port show
pci/0000:06:00.0/65535: type eth netdev ens2f0 flavour physical
pci/0000:05:00.0/1: type eth netdev eth1 flavour pcivf pfnum 0 vfnum 0
pci/0000:05:00.0/2: type eth netdev eth2 flavour pcivf pfnum 0 vfnum 1

Reviewed-by: Roi Dayan <roid@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>