i40e: Add ndo_get_phys_port_id() callback support

This patch adds a new API to get the port mac address from firmware.
It also adds support to the ndo_get_phys_port_id() callback to provide
port specific unique id to the netdev layer.
If the adapter has a valid per-port mac address then that
would be used for this purpose and is expected to be unique
on a per-port basis.

The information can be viewed by reading the phys_port_id
attribute in sysfs for each netdev or via IF netlink
interface.

Change-ID: I341fa6fff9c112f1f6d987189309e730e0b50e8b
Signed-off-by: Neerav Parikh <neerav.parikh@intel.com>
Acked-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>