leds: Add driver for PC Engines APU/APU2 LEDs

This patch implements the driver to support the front panel LEDs
for PC Engines APU and APU2 boards.

Signed-off-by: Alan Mizrahi <alan@mizrahi.com.ve>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
3 files changed