arm64: dts: allwinner: h616: Add OrangePi Zero 2 board support

The OrangePi Zero 2 is a development board with the new H616 SoC. It
comes with the following features:
  - Four ARM Cortex-A53 cores, Mali-G31 MP2 GPU
  - 512MiB/1GiB DDR3 DRAM
  - AXP305 PMIC
  - Raspberry-Pi-1 compatible GPIO header
  - extra 13 pin expansion header, exposing pins for 2x USB 2.0 ports
  - 1 USB 2.0 host port
  - 1 USB 2.0 type C port (power supply + OTG)
  - MicroSD slot
  - on-board 2MiB bootable SPI NOR flash
  - 1Gbps Ethernet port (via RTL8211F PHY)
  - micro-HDMI port
  - (yet) unsupported Allwinner WiFi/BT chip

Add the devicetree file describing the currently supported features.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20220708105235.3983266-7-andre.przywara@arm.com