arm64: dts: rockchip: Use NCM6A-IO board for edgeble-neu6b

arm64: dts: rockchip: Use NCM6A-IO board for edgeble-neu6b

Edgeble AI 6TOPS board topology is now changed in final revisions
as a compatible IO board, NCM6A-IO, is made available for both
variants of SoM: NCM6A and NCM6B.

With this change, 6b-io is not as available and 6a; 6b SoM's have
the same compatible IO board as 6a-io. This change is due to the
common optimised design of the IO board made available now in
final revisions, which was not the case in initial revisions.

So, use the NCM6A-IO compatible for NCM6B SoM based IO dts.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231125142914.57459-2-jagan@edgeble.ai
Signed-off-by: Heiko Stuebner <heiko@sntech.de>