SPRD Idle States for cpuidle driver

The devicetree representation of the idle state should be -

Required properties:

- compatible: Must be -
	 "sprd,pike2-idle-state".

Other required and optional properties are specified in
Documentation/devicetree/bindings/arm/idle-states.txt

Example:

	idle-states {
		LIGHT_SLEEP: light_sleep {
			compatible = "sprd,pike2-idle-state";
			entry-latency-us = <1000>;
			exit-latency-us = <700>;
			min-residency-us = <2500>;
			local-timer-stop;
			arm,psci-suspend-param = <0x00010002>;
		};
		HEAVY_SLEEP: heavy_sleep {
			compatible = "sprd,pike2-idle-state";
			entry-latency-us = <1000>;
			exit-latency-us = <1000>;
			min-residency-us = <3000>;
			local-timer-stop;
			arm,psci-suspend-param = <0x01010003>;
		};
	};
