arm64: dts: rockchip: Add Asus Tinker Board 3 and 3S device tree

arm64: dts: rockchip: Add Asus Tinker Board 3 and 3S device tree

Add initial device tree support for Asus Tinker Board 3 [1] and 3S [2],
which are SBCs based on the Rockchip 3566 SoC.

The "3S" version ("S" for "storage") just adds a 16 GB eMMC
and a "mask ROM" DIP switch (to mask the eMMC and enter "Mask ROM"
mode for recovery) to the "3" version.

This adds support for:
- Debug UART (/dev/ttyS2)
- SD card (/dev/mmcblk1)
- eMMC (/dev/mmcblk0, only on Tinker Board 3S)
- I2C:
  - i2c0 (internal bus with a PMIC and regulators)
  - i2c2 (internal bus with an at24 eeprom and an RTC device)
- USB 2.0 ports
- 2 GPIO LEDS

[1] https://tinker-board.asus.com/series/tinker-board-3.html
[2] https://tinker-board.asus.com/series/tinker-board-3s.html

Signed-off-by: Michael Opdenacker <michael.opdenacker@rootcommit.com>
Link: https://patch.msgid.link/20251118-tinker3-v3-2-2903693f2ebb@rootcommit.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>