arm64: dts: socfpga: agilex5: add NAND daughter board

The Agilex5 devkit supports a separate NAND daughter card.
The NAND daughter card replaces the SDMMC slot that is on the default
daughter card thus requires a separate board dts file.

Signed-off-by: Niravkumar L Rabara <niravkumar.l.rabara@intel.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>