Refactor virtio-net to use generic get_vhost_net This decouples virtio-net from the TAP netdev backend and allows support for other backends to be implemented. Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com> Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>