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

Add a new compatible string "ti,am654-ecap" to support PWM ECAP IP of
TI AM654 SoC.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

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

@@ -7,6 +7,7 @@ Required properties:
   for da850  - compatible = "ti,da850-ecap", "ti,am3352-ecap", "ti,am33xx-ecap";
   for dra746 - compatible = "ti,dra746-ecap", "ti,am3352-ecap";
   for 66ak2g - compatible = "ti,k2g-ecap", "ti,am3352-ecap";
+  for am654  - compatible = "ti,am654-ecap", "ti,am3352-ecap";
 - #pwm-cells: should be 3. See pwm.txt in this directory for a description of
   the cells format. The PWM channel index ranges from 0 to 4. The only third
   cell flag supported by this binding is PWM_POLARITY_INVERTED.