ARM: dts: sun9i: Add GPIO LEDs for A80 Optimus board

The A80 Optimus board has 3 usable LEDs that are controlled via GPIO.

This patch adds support for 2 of them which are driver by GPIOs in the
main pin controller. The remaining one uses GPIO from the R_PIO
controller, which we don't support yet.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>