arm64: dts: socfpga: stratix10_socdk: align NAND chip name with bindings

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>

arch/arm64/boot/dts/altera/socfpga_stratix10_socdk_nand.dts

@@ -102,7 +102,7 @@ phy0: ethernet-phy@0 {
 &nand {
 	status = "okay";
 
-	flash@0 {
+	nand@0 {
 		reg = <0>;
 		#address-cells = <1>;
 		#size-cells = <1>;