tools/virtio: more stubs

As usual, add more stubs to fix test build after main
codebase changes.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --cc tools/virtio/linux/virtio.h
Simple merge

diff --cc tools/virtio/linux/virtio_byteorder.h
Simple merge

diff --cc tools/virtio/linux/virtio_config.h
Simple merge

diff --cc tools/virtio/uapi/linux/virtio_types.h
Simple merge

diff --cc tools/virtio/virtio_test.c
Simple merge