dt-bindings: Add dt bindings for jtagv8 driver

* JTAG-MM

The jtag-mm entry specifies the memory mapped addresses for the debug and ETM

registers. The jtag-mm driver uses these to save and restore the registers

using memory mapped access during power collapse so as to retain their state

across power collapse. This is necessary in case cp14 access to the registers

is not permitted.

Required Properties:

compatible: component name used for driver matching, should be:

	"qcom,jtag-mm"		- for jtag-mm device

	"qcom,jtagv8-mm"	- for jtagv8-mm device supporting ARMv8 targets

	reg: physical base address and length of the register set

	reg-names: should be "etm-base" for etm register set and "debug-base"

		   for debug register set.

	qcom,coresight-jtagmm-cpu: specifies phandle for the cpu associated

				   with the jtag-mm device

	qcom,si-enable : boolean, indicating etm save and restore is

			 supported via system instructions

	qcom,save-restore-disable : boolean, to disable etm save and restore

				    functionality

Example:

jtag_mm: jtagmm@fc332000 {

	compatible = "qcom,jtag-mm";

	reg = <0xfc332000 0x1000>,

		<0xfc333000 0x1000>;

	reg-names = "etm-base","debug-base";

	qcom,coresight-jtagmm-cpu = <&CPU0>;

};