arm64: dts: rockchip: Add Edgeble NCM6A-IO M.2 M-Key

Edgeble NCM6A-IO board has M.2 M-Key via PCI3x4.

Add support for it.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Link: https://lore.kernel.org/r/20231125190522.87607-8-jagan@edgeble.ai


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