devlink: Introduce PCI PF port flavour and port attribute

In an eswitch, PCI PF may have port which is normally represented
using a representor netdevice.
To have better visibility of eswitch port, its association with
PF and a representor netdevice, introduce a PCI PF port
flavour and port attriute.

When devlink port flavour is PCI PF, fill up PCI PF attributes of the
port.

Extend port name creation using PCI PF number on best effort basis.
So that vendor drivers can skip defining their own scheme.

$ devlink port show
pci/0000:05:00.0/0: type eth netdev eth0 flavour pcipf pfnum 0

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