mtd: nand: sunxi: 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>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/sunxi_nand.c

@@ -1391,8 +1391,10 @@ static int sunxi_nand_chips_init(struct device *dev, struct sunxi_nfc *nfc)
 
 	for_each_child_of_node(np, nand_np) {
 		ret = sunxi_nand_chip_init(dev, nfc, nand_np);
-		if (ret)
+		if (ret) {
+			of_node_put(nand_np);
 			return ret;
+		}
 	}
 
 	return 0;