ARM: dts: BCM63xx: Fix NAND nodes names

This matches nand-controller.yaml requirements.

Signed-off-by: Rafał Miłecki <[e-mail]>
Signed-off-by: Florian Fainelli <[e-mail]>

arch/arm/boot/dts/bcm63138.dtsi

···
 			status = "disabled";
 		};
 
-		nand: nand@2000 {
+		nand_controller: nand-controller@2000 {
 			#address-cells = <1>;
 			#size-cells = <0>;
 			compatible = "brcm,nand-bcm63138", "brcm,brcmnand-v7.0", "brcm,brcmnand";

arch/arm/boot/dts/bcm963138dvt.dts

···
 	status = "okay";
 };
 
-&nand {
+&nand_controller {
 	status = "okay";
 
-	nandcs@0 {
+	nand@0 {
 		compatible = "brcm,nandcs";
 		reg = <0>;
 		nand-ecc-strength = <4>;