arm64: dts: ls1088a: add cpu idle support

ls1088a supports another cpu idle state which is ph20 which saves
more power when cpu is idle.
It was implemented through psci firmware.
Signed-off-by: NTang Yuantian <andy.tang@nxp.com>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi

@@ -66,6 +66,7 @@
 			compatible = "arm,cortex-a53";
 			reg = <0x0>;
 			clocks = <&clockgen 1 0>;
+			cpu-idle-states = <&CPU_PH20>;
 			#cooling-cells = <2>;
 		};
 
@@ -74,6 +75,7 @@
 			compatible = "arm,cortex-a53";
 			reg = <0x1>;
 			clocks = <&clockgen 1 0>;
+			cpu-idle-states = <&CPU_PH20>;
 		};
 
 		cpu2: cpu@2 {
@@ -81,6 +83,7 @@
 			compatible = "arm,cortex-a53";
 			reg = <0x2>;
 			clocks = <&clockgen 1 0>;
+			cpu-idle-states = <&CPU_PH20>;
 		};
 
 		cpu3: cpu@3 {
@@ -88,6 +91,7 @@
 			compatible = "arm,cortex-a53";
 			reg = <0x3>;
 			clocks = <&clockgen 1 0>;
+			cpu-idle-states = <&CPU_PH20>;
 		};
 
 		cpu4: cpu@100 {
@@ -95,6 +99,7 @@
 			compatible = "arm,cortex-a53";
 			reg = <0x100>;
 			clocks = <&clockgen 1 1>;
+			cpu-idle-states = <&CPU_PH20>;
 			#cooling-cells = <2>;
 		};
 
@@ -103,6 +108,7 @@
 			compatible = "arm,cortex-a53";
 			reg = <0x101>;
 			clocks = <&clockgen 1 1>;
+			cpu-idle-states = <&CPU_PH20>;
 		};
 
 		cpu6: cpu@102 {
@@ -110,6 +116,7 @@
 			compatible = "arm,cortex-a53";
 			reg = <0x102>;
 			clocks = <&clockgen 1 1>;
+			cpu-idle-states = <&CPU_PH20>;
 		};
 
 		cpu7: cpu@103 {
@@ -117,6 +124,16 @@
 			compatible = "arm,cortex-a53";
 			reg = <0x103>;
 			clocks = <&clockgen 1 1>;
+			cpu-idle-states = <&CPU_PH20>;
+		};
+
+		CPU_PH20: cpu-ph20 {
+			compatible = "arm,idle-state";
+			idle-state-name = "PH20";
+			arm,psci-suspend-param = <0x00010000>;
+			entry-latency-us = <1000>;
+			exit-latency-us = <1000>;
+			min-residency-us = <3000>;
 		};
 	};
 
@@ -140,6 +157,11 @@
 			     <1 10 IRQ_TYPE_LEVEL_LOW>;/* Hypervisor PPI */
 	};
 
+	psci {
+		compatible = "arm,psci-0.2";
+		method = "smc";
+	};
+
 	sysclk: sysclk {
 		compatible = "fixed-clock";
 		#clock-cells = <0>;