QTI CPU hotplug cooling devices.

The CPU hotplug cooling device will be used for hotpluging a CPU on a thermal
condition. This cooling device driver can register one cooling device per CPU,
which can be used by thermal zone to mitigate.

Each child node will represent a cooling device and the child node should
point to the CPU, which will be mitigated by that cooling device instance.

Properties:
- compatible:
	Usage: required
	Value type: <string>
	Definition: should be "qcom,cpu-hotplug"

Cooling device node:
- qcom,cpu:
	Usage: required
	Value type: <phandle>
	Definition: phandle to the CPU device that this cooling device will
			mitigate.

-#cooling-cells:
	Usage: required
	Value type: <integer>
	Definition: Must be 2. Needed for of_thermal as cooling device
			identifier. Please refer to
			<devicetree/bindings/thermal/thermal.txt> for more
			details.
Example:
	qcom,cpu-hotplug {
		compatible = "qcom,cpu-hotplug";

		cpu0_hotplug: cpu0-hotplug {
			qcom,cpu = <&CPU0>;
			#cooling-cells = <2>;
		};
		cpu1_hotplug: cpu1-hotplug {
			qcom,cpu = <&CPU1>;
			#cooling-cells = <2>;
		};
		cpu2_hotplug: cpu2-hotplug {
			qcom,cpu = <&CPU2>;
			#cooling-cells = <2>;
		};
		cpu3_hotplug: cpu3-hotplug {
			qcom,cpu = <&CPU3>;
			#cooling-cells = <2>;
		};
        };
