Texas Instruments Debug Sub-System (DebugSS) module for Keystone devices

Required properties:
- compatible : Should be "ti,keystone-debugss"

Optional properties:
- clocks : the clocks feeding the Debug sub-system.
	   As an exception, the mainpllclk and
	   armpllclk are not directly feeding
	   the debugss, instead they are used
	   by the debugss module to expose the
	   mainpll and armpll clock rates as
	   sysfs entries readable from userspace
	   applications.
	   Needed if platform uses clocks.
	   See clock-bindings.txt
- clocks-names : clock name strings correspond to the clocks
		 defined above. These strings are used inside
		 module source code to identify the respective
                 clocks

Documentation:
http://www.ti.com/lit/ug/spruhm4/spruhm4.pdf
http://www.ti.com/lit/ds/symlink/tci6636k2h.pdf

Examples:

debugss: debugss {
        compatible = "ti,keystone-debugss";
        clocks = <&mainpllclk>, <&armpllclk>, <&clkdebugsstrc>, <&gemtraceclk>, <&clktetbtrc>;
        clock-names = "mainpllclock", "armpllclock", "debugssclock", "gemtraceclock", "tetbclock";
};