virtio-balloon: switch to virtio_add_feature

This was missed during the conversion of feature bit manipulation.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

hw/virtio/virtio-balloon.c

@@ -312,7 +312,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
 
 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f)
 {
-    f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
+    virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
     return f;
 }