vhost: fix packed virtqueue ready condition

Consider a virtqueue ready when, apart from the descriptor area,
both event suppression areas have been mapped.

Fixes: 2d1541e2b6 ("vhost: add vring address setup for packed queues")
Cc: stable@dpdk.org

Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>

lib/librte_vhost/vhost_user.c

@@ -1298,7 +1298,8 @@ vq_is_ready(struct virtio_net *dev, struct vhost_virtqueue *vq)
 		return false;
 
 	if (vq_is_packed(dev))
-		rings_ok = !!vq->desc_packed;
+		rings_ok = vq->desc_packed && vq->driver_event &&
+			vq->device_event;
 	else
 		rings_ok = vq->desc && vq->avail && vq->used;