arm64: dts: rockchip: add DTs for Sakura Pi RK3308B

arm64: dts: rockchip: add DTs for Sakura Pi RK3308B

The Sakura Pi RK3308B is a SBC based on the Rockchip RK3308 SoC.

Link: https://github.com/Sakura-Pi
Link: https://docs.sakurapi.org/article/sakurapi-rk3308b/introduce
The device contains the following hardware that is tested/working:
 - 4 or 8GB eMMC
 - SDMMC card slot
 - Realtek SDIO WiFi 5/BT
 - 256 or 512MB of RAM
 - USB 2.0 port
 - OTG port

Signed-off-by: Hsun Lai <i@chainsx.cn>
Link: https://lore.kernel.org/r/20250521131108.5710-4-i@chainsx.cn
Signed-off-by: Heiko Stuebner <heiko@sntech.de>