Adreno bus monitor device

kgsl-busmon is a psedo device that represents a devfreq bus bandwidth
governor. If this device is present then two different governors are used
for  GPU DCVS and bus DCVS.

Required properties:
- compatible:	Must be "qcom,kgsl-busmon"
- label:	Device name used for sysfs entry.

Example:

	qcom,kgsl-busmon {
		compatible = "qcom,kgsl-busmon";
		label = "kgsl-busmon";
	};