Add a driver framework for the Compute Engine Virtual NIC that will be
available in the future.

At this point the only functionality is loading the driver.
Signed-off-by: NCatherine Sullivan <csully@google.com>
Signed-off-by: NSagi Shahar <sagis@google.com>
Signed-off-by: NJon Olson <jonolson@google.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Reviewed-by: NLuigi Rizzo <lrizzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>