arm64: dts: rockchip: Add common DT for edgeble-neu6b-io

Edgeble Neu6a and Neu6b are compatible with common IO board.

So, maintain the IO board in rk3588-edgeble-neu6a-io.dtsi.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Link: https://lore.kernel.org/r/20231125190522.87607-4-jagan@edgeble.ai


Signed-off-by: Heiko Stuebner <heiko@sntech.de>