ARM: 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=arm 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/arm/boot/dts/uniphier-ld4.dtsi

@@ -398,7 +398,7 @@ sys_rst: reset {
 			};
 		};
 
-		nand: nand@68000000 {
+		nand: nand-controller@68000000 {
 			compatible = "socionext,uniphier-denali-nand-v5a";
 			status = "disabled";
 			reg-names = "nand_data", "denali_reg";

arch/arm/boot/dts/uniphier-pro4.dtsi

@@ -588,7 +588,7 @@ usb1_rst: reset@40 {
 			};
 		};
 
-		nand: nand@68000000 {
+		nand: nand-controller@68000000 {
 			compatible = "socionext,uniphier-denali-nand-v5a";
 			status = "disabled";
 			reg-names = "nand_data", "denali_reg";

arch/arm/boot/dts/uniphier-pro5.dtsi

@@ -453,7 +453,7 @@ sys_rst: reset {
 			};
 		};
 
-		nand: nand@68000000 {
+		nand: nand-controller@68000000 {
 			compatible = "socionext,uniphier-denali-nand-v5b";
 			status = "disabled";
 			reg-names = "nand_data", "denali_reg";

arch/arm/boot/dts/uniphier-pxs2.dtsi

@@ -761,7 +761,7 @@ usb1_ssphy0: ss-phy@300 {
 			};
 		};
 
-		nand: nand@68000000 {
+		nand: nand-controller@68000000 {
 			compatible = "socionext,uniphier-denali-nand-v5b";
 			status = "disabled";
 			reg-names = "nand_data", "denali_reg";

arch/arm/boot/dts/uniphier-sld8.dtsi

@@ -402,7 +402,7 @@ sys_rst: reset {
 			};
 		};
 
-		nand: nand@68000000 {
+		nand: nand-controller@68000000 {
 			compatible = "socionext,uniphier-denali-nand-v5a";
 			status = "disabled";
 			reg-names = "nand_data", "denali_reg";