drivers/of: Export OF changeset functions

The PowerNV PCI hotplug driver is going to use the OF changeset
to manage the changed device sub-tree. This exports those OF
changeset functions for that.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 54e5af9..8225081 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -379,9 +379,9 @@
 	}
 
 	/* apply the changeset */
-	err = of_changeset_apply(&ov->cset);
+	err = __of_changeset_apply(&ov->cset);
 	if (err) {
-		pr_err("%s: of_changeset_apply() failed for tree@%s\n",
+		pr_err("%s: __of_changeset_apply() failed for tree@%s\n",
 				__func__, tree->full_name);
 		goto err_revert_overlay;
 	}
@@ -511,7 +511,7 @@
 
 
 	list_del(&ov->node);
-	of_changeset_revert(&ov->cset);
+	__of_changeset_revert(&ov->cset);
 	of_free_overlay_info(ov);
 	idr_remove(&ov_idr, id);
 	of_changeset_destroy(&ov->cset);
@@ -542,7 +542,7 @@
 	/* the tail of list is guaranteed to be safe to remove */
 	list_for_each_entry_safe_reverse(ov, ovn, &ov_list, node) {
 		list_del(&ov->node);
-		of_changeset_revert(&ov->cset);
+		__of_changeset_revert(&ov->cset);
 		of_free_overlay_info(ov);
 		idr_remove(&ov_idr, ov->id);
 		kfree(ov);