hwmon: add GPD devices sensor driver

hwmon: add GPD devices sensor driver

Sensors driver for GPD Handhelds that expose fan reading and control via
hwmon sysfs.

Shenzhen GPD Technology Co., Ltd. manufactures a series of handheld
devices. This driver implements these functions through x86 port-mapped
IO.

Tested-by: Marcin Strągowski <marcin@stragowski.com>
Tested-by: someone5678 <someone5678.dev@gmail.com>
Tested-by: Justin Weiss <justin@justinweiss.com>
Tested-by: Antheas Kapenekakis <lkml@antheas.dev>
Tested-by: command_block <mtf@ik.me>
Tested-by: derjohn <himself@derjohn.de>
Tested-by: Crashdummyy <crashdummy1337@proton.me>
Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
Link: https://lore.kernel.org/r/20250908-gpd_fan-v9-1-7b4506c03953@uniontech.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>