arm64: zynqmp: Add references to cpu nodes

Add missing references to all cpu nodes.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/dts/zynqmp.dtsi

@@ -17,7 +17,7 @@
 		#address-cells = <1>;
 		#size-cells = <0>;
 
-		cpu@0 {
+		cpu0: cpu@0 {
 			compatible = "arm,cortex-a53", "arm,armv8";
 			device_type = "cpu";
 			enable-method = "psci";
@@ -25,7 +25,7 @@
 			cpu-idle-states = <&CPU_SLEEP_0>;
 		};
 
-		cpu@1 {
+		cpu1: cpu@1 {
 			compatible = "arm,cortex-a53", "arm,armv8";
 			device_type = "cpu";
 			enable-method = "psci";
@@ -33,7 +33,7 @@
 			cpu-idle-states = <&CPU_SLEEP_0>;
 		};
 
-		cpu@2 {
+		cpu2: cpu@2 {
 			compatible = "arm,cortex-a53", "arm,armv8";
 			device_type = "cpu";
 			enable-method = "psci";
@@ -41,7 +41,7 @@
 			cpu-idle-states = <&CPU_SLEEP_0>;
 		};
 
-		cpu@3 {
+		cpu3: cpu@3 {
 			compatible = "arm,cortex-a53", "arm,armv8";
 			device_type = "cpu";
 			enable-method = "psci";