virtio: pm: use CONFIG_PM_SLEEP instead of CONFIG_PM

The freeze and restore functions defined in virtio drivers are used
for suspend and hibernate, so CONFIG_PM_SLEEP is more appropriate than
CONFIG_PM. This patch replace all CONFIG_PM with CONFIG_PM_SLEEP for
virtio drivers that implement freeze and restore callbacks.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index defec2b..2ad3d96 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1683,7 +1683,7 @@
 	free_netdev(vi->dev);
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 static int virtnet_freeze(struct virtio_device *vdev)
 {
 	struct virtnet_info *vi = vdev->priv;
@@ -1766,7 +1766,7 @@
 	.probe =	virtnet_probe,
 	.remove =	virtnet_remove,
 	.config_changed = virtnet_config_changed,
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 	.freeze =	virtnet_freeze,
 	.restore =	virtnet_restore,
 #endif