virtio: balloon: drop restore_common()

restore_common() was used when there were different thaw and freeze PM
callbacks implemented.  We removed thaw in commit
f38f8387.

restore_common() can be removed and virtballoon_restore() can itself do
the restore ops.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/virtio/virtio_balloon.c

@@ -419,7 +419,7 @@ static int virtballoon_freeze(struct virtio_device *vdev)
 	return 0;
 }
 
-static int restore_common(struct virtio_device *vdev)
+static int virtballoon_restore(struct virtio_device *vdev)
 {
 	struct virtio_balloon *vb = vdev->priv;
 	int ret;
@@ -432,11 +432,6 @@ static int restore_common(struct virtio_device *vdev)
 	update_balloon_size(vb);
 	return 0;
 }
-
-static int virtballoon_restore(struct virtio_device *vdev)
-{
-	return restore_common(vdev);
-}
 #endif
 
 static unsigned int features[] = {