arm64: dts: rockchip: add Odroid Advance Go

The Odroid Advance Go is a handheld based on Rockchip's rk3326 soc
with a DSI display and some handheld controls including an analog
joystick connected to the saradc.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Link: https://lore.kernel.org/r/20200414082938.2977572-3-heiko@sntech.de


Signed-off-by: Heiko Stuebner <heiko@sntech.de>