net: rfkill: gpio: Switch to devm_acpi_dev_add_driver_gpios()

Switch to use managed variant of acpi_dev_add_driver_gpios() to simplify
error path and fix potentially wrong assingment if ->probe() fails.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>