arm64: dts: uniphier: rename NAND node names to follow json-schema

Follow the standard nodename pattern "^nand-controller(@.*)?" defined
in Documentation/devicetree/bindings/mtd/nand-controller.yaml

Otherwise, after the dt-binding is converted to json-schema,
'make ARCH=arm64 dtbs_check' will show warnings like this:

  nand@68000000: $nodename:0: 'nand@68000000' does not match '^nand-controller(@.*)?'
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/arm64/boot/dts/socionext/uniphier-ld11.dtsi

@@ -621,7 +621,7 @@ mdio: mdio {
 			};
 		};
 
-		nand: nand@68000000 {
+		nand: nand-controller@68000000 {
 			compatible = "socionext,uniphier-denali-nand-v5b";
 			status = "disabled";
 			reg-names = "nand_data", "denali_reg";

arch/arm64/boot/dts/socionext/uniphier-ld20.dtsi

@@ -925,7 +925,7 @@ pcie_phy: phy@66038000 {
 			socionext,syscon = <&soc_glue>;
 		};
 
-		nand: nand@68000000 {
+		nand: nand-controller@68000000 {
 			compatible = "socionext,uniphier-denali-nand-v5b";
 			status = "disabled";
 			reg-names = "nand_data", "denali_reg";

arch/arm64/boot/dts/socionext/uniphier-pxs3.dtsi

@@ -783,7 +783,7 @@ pcie_phy: phy@66038000 {
 			socionext,syscon = <&soc_glue>;
 		};
 
-		nand: nand@68000000 {
+		nand: nand-controller@68000000 {
 			compatible = "socionext,uniphier-denali-nand-v5b";
 			status = "disabled";
 			reg-names = "nand_data", "denali_reg";