Add a driver for the GPD pocket device's custom fan controller, which
gets controlled through 2 GPIOs listed in a FAN02501 ACPI device.

Cc: James <kernel@madingley.org>
Suggested-by: James <kernel@madingley.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>