arm64: dts: rockchip: Add Hardkernel ODROID-M1 board

This patch is to add a device tree for new board Hardkernel ODROID-M1
based on Rockchip RK3568, includes basic peripherals -
uart/eMMC/uSD/i2c and on-board ethernet.

Signed-off-by: Dongjin Kim <tobetter@gmail.com>
[aurelien@aurel32.net: addressed issues from initial review]
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: Dan Johansen <strit@manjaro.org>
Link: https://lore.kernel.org/r/20220930051246.391614-3-aurelien@aurel32.net
Signed-off-by: Heiko Stuebner <heiko@sntech.de>