devlink: Support get port function state

devlink: Support get port function state

Print port function state and operational state whenever reported by
kernel.

Example of a PCI SF port function which supports the state:

$ devlink dev eswitch set pci/0000:06:00.0 mode switchdev

$ devlink port show
pci/0000:06:00.0/65535: type eth netdev ens2f0np0 flavour physical port 0 splittable false

$ devlink port add pci/0000:06:00.0 flavour pcisf pfnum 0 sfnum 88
pci/0000:08:00.0/32768: type eth netdev eth6 flavour pcisf controller 0 pfnum 0 sfnum 88 splittable false
  function:
    hw_addr 00:00:00:00:00:00 state inactive opstate detached

$ devlink port show pci/0000:06:00.0/32768
pci/0000:06:00.0/32768: type eth netdev ens2f0npf0sf88 flavour pcisf controller 0 pfnum 0 sfnum 88 splittable false
  function:
    hw_addr 00:00:00:00:00:00 state inactive opstate detached

$ devlink port function set pci/0000:06:00.0/32768 hw_addr 00:00:00:00:88:88

$ devlink port show pci/0000:06:00.0/32768 -jp
{
    "port": {
        "pci/0000:06:00.0/32768": {
            "type": "eth",
            "netdev": "ens2f0npf0sf88",
            "flavour": "pcisf",
            "controller": 0,
            "pfnum": 0,
            "sfnum": 88,
            "splittable": false,
            "function": {
                "hw_addr": "00:00:00:00:88:88",
                "state": "inactive",
                "opstate": "detached"
            }
        }
    }
}

Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David Ahern <dsahern@kernel.org>