arm64: dts: rockchip: Add support for the Orange Pi RK3399 board.

This adds basic support for the Orange Pi RK3399 board.
What works:
- SD card / emmc.
- Debug UART
- Ethernet
- USB: Type C, internal USB3 for SATA, 4 USB 2.0 ports
- Sensors: All of them but the Hall sensor.
- Buttons
- Wifi, Bluetooth
- HDMI out

Signed-off-by: Alexis Ballier <aballier@gentoo.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>