virtio: rng: don't wait on host when module is going away

No use waiting for input from host when the module is being removed.
We're going to remove the vq in the next step anyway, so just perform
any other steps for cleanup (currently none).
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/char/hw_random/virtio-rng.c

@@ -109,6 +109,7 @@ static int virtrng_probe(struct virtio_device *vdev)
 static void __devexit virtrng_remove(struct virtio_device *vdev)
 {
 	vdev->config->reset(vdev);
+	busy = false;
 	hwrng_unregister(&virtio_hwrng);
 	vdev->config->del_vqs(vdev);
 }