dt-bindings: rockchip: Add Hardkernel ODROID-M1 board

Add device tree binding for Hardkernel ODROID-M1 board based on RK3568
SoC.

Signed-off-by: Dongjin Kim <tobetter@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Dan Johansen <strit@manjaro.org>
Link: https://lore.kernel.org/r/20220930051246.391614-2-aurelien@aurel32.net
Signed-off-by: Heiko Stuebner <heiko@sntech.de>