SR-IOV support has been added to Hyper-V since Windows / Hyper-V
Server 2012.
In order to properly use SR-IOV, the host must support it, and have it
enabled, and it must have SR-IOV capable NICs.
The Hyper-V vSwitches will have to be configured to enable SR-IOV.
vmutils: create_nic - mac_address can now be None. If None,
a dynamic address will be used instead.
hostuils: added get_nic_sriov_vfs - returns a list of dictionaries,
containing available vSwitch VFs.
networkutils: added set_vswitch_port_sriov - enables / disables SR-IOV
on the given switch port.
Implements: blueprint os-win-sriov
Change-Id: Ied27bb4e1b36e743b33c6b65351c2ee942ef535e