ARM: at91: pm: call put_device instead of of_node_put in at91_pm_config_ws
of_find_device_by_node takes a reference to the struct device when it
finds a match via get_device. but it fails to put_device in
at91_pm_config_ws, for_each_matching_node_and_match will get and put
the node properly, there is no need to call the of_put_node. Therefore,
just call put_device instead of of_node_put in at91_pm_config_ws.