hwmon: (tmp421) Add of_node_put() before return

Fix following coccicheck warning:
./drivers/hwmon/tmp421.c:416:1-23: WARNING: Function
for_each_child_of_node should have of_node_put() before return.

Early exits from for_each_child_of_node should decrement the
node reference counter.
Signed-off-by: NWan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20211018121538.16482-1-wanjiabing@vivo.comSigned-off-by: NGuenter Roeck <linux@roeck-us.net>

drivers/hwmon/tmp421.c

@@ -418,9 +418,11 @@ static int tmp421_probe_from_dt(struct i2c_client *client, struct tmp421_data *d
 			continue;
 
 		err = tmp421_probe_child_from_dt(client, child, data);
-		if (err)
+		if (err) {
+			of_node_put(child);
 			return err;
 		}
+	}
 
 	return 0;
 }