hwmon: (aspeed-pwm-tacho) Call of_node_put() on a node not claimed

Call of_node_put() on a node claimed with of_node_get() or by any other
means such as for_each_child_of_node().

Signed-off-by: Stefan Schaeckeler <sschaeck@cisco.com>
Fixes: 2d7a548a ("drivers: hwmon: Support for ASPEED PWM/Fan tach")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>