[media] v4l: xilinx-tpg: 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>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/platform/xilinx/xilinx-tpg.c

@@ -731,6 +731,7 @@ static int xtpg_parse_of(struct xtpg_device *xtpg)
 		format = xvip_of_get_format(port);
 		if (IS_ERR(format)) {
 			dev_err(dev, "invalid format in DT");
+			of_node_put(port);
 			return PTR_ERR(format);
 		}
 
@@ -739,6 +740,7 @@ static int xtpg_parse_of(struct xtpg_device *xtpg)
 			xtpg->vip_format = format;
 		} else if (xtpg->vip_format != format) {
 			dev_err(dev, "in/out format mismatch in DT");
+			of_node_put(port);
 			return -EINVAL;
 		}