arm64: dts: mediatek: Add cpuidle support for MT2712

Add CPU idle state nodes to enable C1/C2 idle states.
Signed-off-by: James Liao <jamesjj.liao@mediatek.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt2712e.dtsi

@@ -39,6 +39,7 @@ cpu0: cpu@0 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a35";
 			reg = <0x000>;
+			cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
 		};
 
 		cpu1: cpu@1 {
@@ -46,6 +47,7 @@ cpu1: cpu@1 {
 			compatible = "arm,cortex-a35";
 			reg = <0x001>;
 			enable-method = "psci";
+			cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
 		};
 
 		cpu2: cpu@200 {
@@ -53,6 +55,29 @@ cpu2: cpu@200 {
 			compatible = "arm,cortex-a72";
 			reg = <0x200>;
 			enable-method = "psci";
+			cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
+		};
+
+		idle-states {
+			entry-method = "arm,psci";
+
+			CPU_SLEEP_0: cpu-sleep-0 {
+				compatible = "arm,idle-state";
+				local-timer-stop;
+				entry-latency-us = <100>;
+				exit-latency-us = <80>;
+				min-residency-us = <2000>;
+				arm,psci-suspend-param = <0x0010000>;
+			};
+
+			CLUSTER_SLEEP_0: cluster-sleep-0 {
+				compatible = "arm,idle-state";
+				local-timer-stop;
+				entry-latency-us = <350>;
+				exit-latency-us = <80>;
+				min-residency-us = <3000>;
+				arm,psci-suspend-param = <0x1010000>;
+			};
 		};
 	};