board: rockchip: Add support for Powkiddy RGB10MAX3

Add support to the RGxx3 device for the Powkiddy RGB10MAX3. This device
is extremely similar to all the other devices and can use the same
bootloader with the same detection logic.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>