dt-bindings: pwm: tiehrpwm: Add TI AM654 SoC specific compatible

Add a new compatible string "ti,am654-ehrpwm" to support EHRPWM IP on
TI AM654 SoC.
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

Documentation/devicetree/bindings/pwm/pwm-tiehrpwm.txt

@@ -4,6 +4,7 @@ Required properties:
 - compatible: Must be "ti,<soc>-ehrpwm".
   for am33xx  - compatible = "ti,am3352-ehrpwm", "ti,am33xx-ehrpwm";
   for am4372  - compatible = "ti,am4372-ehrpwm", "ti-am3352-ehrpwm", "ti,am33xx-ehrpwm";
+  for am654   - compatible = "ti,am654-ehrpwm", "ti-am3352-ehrpwm";
   for da850   - compatible = "ti,da850-ehrpwm", "ti-am3352-ehrpwm", "ti,am33xx-ehrpwm";
   for dra746 - compatible = "ti,dra746-ehrpwm", "ti-am3352-ehrpwm";
 - #pwm-cells: should be 3. See pwm.txt in this directory for a description of