[SCSI] virtio-scsi: initialize scatterlist structure

The sg struct is used without being initialized, which breaks
when CONFIG_DEBUG_SG is enabled.

Cc: stable@vger.kernel.org
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/virtio_scsi.c

@@ -219,7 +219,7 @@ static int virtscsi_kick_event(struct virtio_scsi *vscsi,
 	struct scatterlist sg;
 	unsigned long flags;
 
-	sg_set_buf(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
+	sg_init_one(&sg, &event_node->event, sizeof(struct virtio_scsi_event));
 
 	spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags);