dt-bindings: amlogic: document Odroid Go Ultra compatible

dt-bindings: amlogic: document Odroid Go Ultra compatible

This documents the Odroid Go Ultra, a portable gaming device,
with the following characteristics:
- Amlogic S922X SoC
- RK817 & RK818 PMICs
- 2GiB LPDDR4
- On board 16GiB eMMC
- Micro SD Card slot
- 5inch 854×480 MIPI-DSI TFT LCD
- Earphone stereo jack, 0.5Watt 8Ω Mono speaker
- Li-Polymer 3.7V/4000mAh Battery
- USB-A 2.0 Host Connector
- x16 GPIO Input Buttons
- 2x ADC Analog Joysticks
- USB-C Port for USB2 Device and Charging

Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20221031-b4-odroid-go-ultra-initial-v2-1-a3df1e09b0af@linaro.org
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>