Bindings expect NAND child node name to match certain patterns:

  socfpga_agilex_socdk_nand.dtb: nand-controller@ffb90000: Unevaluated properties are not allowed ('flash@0' was unexpected)
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>