arm64: dts: meson: add support for the WeTek Core 2

arm64: dts: meson: add support for the WeTek Core 2

The WeTek Core2 is a commercial device based on the Amlogic Q200 reference
design but with the following differences:

- 3GB RAM, 32GB eMMC
- Blue and Red LEDs used to signal on/off status
- uart_AO can be accessed after opening the case; soldering required
- USB OTG is not accessible (inside the case)
- Realtek RTL8152 Ethernet (internal USB connection)

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20200719021421.7959-3-christianshewitt@gmail.com