arm64: dts: meson: add initial device-tree for MeCool KIII Pro

MeCool (Videostrong) KIII Pro is based on the Amlogic Q200 reference
board with an S912 chip and the following specs:

- 3GB DDR3 RAM
- 16GB eMMC
- 10/100/1000 Base-T Ethernet
- BCM4335 Wireless (802.11 b/g/n/ac, BT 4.0)
- DVB-C/T/T2/S/S2 (AVL6862TA demod + R912 tuner)
- HDMI 2.0a video
- S/PDIF optical output
- CVBS/Analogue output
- 4x USB 2.0 ports
- IR receiver
- 1x Power button (with integrated blue LED)
- 1x Update/Reset button (underside)
- 1x micro SD card slot

Tested-by: Drazen Spio <drazsp@gmail.com>
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20210402064521.30579-4-christianshewitt@gmail.com