of/overlay: add missing of_node_put

for_each_child_of_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
@@

 for_each_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
(
   return child;
|
+  of_node_put(child);
?  return ...;
)
   ...
 }
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/overlay.c

@@ -149,6 +149,7 @@ static int of_overlay_apply_one(struct of_overlay *ov,
 			pr_err("%s: Failed to apply single node @%s/%s\n",
 					__func__, target->full_name,
 					child->name);
+			of_node_put(child);
 			return ret;
 		}
 	}
@@ -417,8 +418,10 @@ static int overlay_subtree_check(struct device_node *tree,
 		return 1;
 
 	for_each_child_of_node(tree, child) {
-		if (overlay_subtree_check(child, dn))
+		if (overlay_subtree_check(child, dn)) {
+			of_node_put(child);
 			return 1;
+		}
 	}
 
 	return 0;