qemu: install port profile and mac address on netdev hostdevs
These changes are applied only if the hostdev has a parent net device
(i.e. if it was defined as "<interface type='hostdev'>" rather than
just "<hostdev>"). If the parent netdevice has virtual port
information, the original virtualport associate functions are called
(these set and restore both mac and port profile on an
interface). Otherwise, only mac address is set on the device.
Note that This is only supported for SR-IOV Virtual Functions (not for
standard PCI or USB netdevs), and virtualport association is only
supported for 802.1Qbh. For all other types of cards and types of
virtualport, a "Config Unsupported" error is returned and the
operation fails.