gpio: acpi: switch to device_for_each_child_node_scoped()

gpio: acpi: switch to device_for_each_child_node_scoped()

Switch to device_for_each_child_node_scoped() to simplify the code by
removing the need for a call to fwnode_handle_put() in the error path.

This also prevents possible memory leaks if new error paths are added
without the required call to fwnode_handle_put().

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>