devlink: Use controller while building phys_port_name
Now that controller number attribute is available, use it when
building phsy_port_name for external controller ports.
An example devlink port and representor netdev name consist of controller
annotation for external controller with controller number = 1,
for a VF 1 of PF 0:
$ devlink port show pci/0000:06:00.0/2
pci/0000:06:00.0/2: type eth netdev ens2f0c1pf0vf1 flavour pcivf controller 1 pfnum 0 vfnum 1 external true splittable false
function:
hw_addr 00:00:00:00:00:00