tools/virtio: add linux/module.h stub

Make the tool build again after virtio changes broke it.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/tools/virtio/linux/module.h b/tools/virtio/linux/module.h
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tools/virtio/linux/module.h