qdev: add 64bit properties

Needed for virtio features which go from 32bit to 64bit with virtio 1.0

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>