virtio_balloon: header update

add modern header
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

include/hw/virtio/virtio-balloon.h

@@ -25,6 +25,12 @@
 
 typedef struct virtio_balloon_stat VirtIOBalloonStat;
 
+typedef struct virtio_balloon_stat_modern {
+       uint16_t tag;
+       uint8_t reserved[6];
+       uint64_t val;
+} VirtIOBalloonStatModern;
+
 typedef struct VirtIOBalloon {
     VirtIODevice parent_obj;
     VirtQueue *ivq, *dvq, *svq;