MSM BIMC bandwidth monitor device

bimc-bwmon is a device that represents the MSM BIMC bandwidth monitors that
can be used to measure the bandwidth of read/write traffic from the BIMC
master ports. For example, the CPU subsystem sits on one BIMC master port.

Required properties:
- compatible:		Must be "qcom,bimc-bwmon", "qcom,bimc-bwmon2"
			"qcom,bimc-bwmon3" or "qcom,bimc-bwmon4" or
			"qcom,bimc-bwmon5"
- reg:			Pairs of physical base addresses and region sizes of
			memory mapped registers.
- reg-names:		Names of the bases for the above registers. Expected
			bases are: "base", "global_base"
- interrupts:		Lists the threshold IRQ.
- qcom,mport:		The hardware master port that this device can monitor
- qcom,target-dev:	The DT device that corresponds to this master port
- qcom,hw-timer-hz:	Hardware sampling rate in Hz. This field must be
			specified for "qcom,bimc-bwmon4"
Optional properties:
- qcom,byte-mid-match:  Byte count MID match value
- qcom,byte-mid-mask:   Byte count MID mask value
- qcom,count-unit:     Number of bytes monitor counts in
- qcom,msm_bus:		A list of tuples where each tuple consists of a bus
			master port number and a bus slave port number.
- qcom,msm_bus_name:	Name of the DT device voting for the bus.
Example:
	qcom,cpu-bwmon {
		compatible = "qcom,bimc-bwmon";
		reg = <0xfc388000 0x300>, <0xfc381000 0x200>;
		reg-names = "base", "global_base";
		interrupts = <0 183 1>;
		qcom,mport = <0>;
		qcom,target-dev = <&cpubw>;
		qcom,hw-timer-hz = <19200000>;
		qcom,byte-mid-match = <0x1e00>;
		qcom,byte-mid-mask = <0x1e00>;
		qcom,count-unit = <0x100000>;
	};