This adds support for the SuperIO chip nct5104d found on the PC Engines
APU boards, which allows for a handful of additional ports, such as 2x
additional UART pinouts, enabling an external watchdog (no driver for
this functionality yet), and 16 GPIO pins. More info can be found at
https://pcengines.ch/ht_gpio.htm
Thanks to @feckert for helping package this.
Cc: Florian Eckert <Eckert.Florian@googlemail.com>
Signed-off-by: Chris Blake <chrisrblake93@gmail.com>
