dt-bindings: pwm: adi,axi-pwmgen: Increase #pwm-cells to 3

Using 3 cells allows to pass additional flags and is the normal
abstraction for new PWM descriptions. There are no device trees yet to
adapt to this change.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/20241024102554.711689-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Author: ukleinek

Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml

@@ -27,7 +27,7 @@ properties:
     maxItems: 1
 
   "#pwm-cells":
-    const: 2
+    const: 3
 
   clocks:
     maxItems: 1
@@ -44,5 +44,5 @@ examples:
        compatible = "adi,axi-pwmgen-2.00.a";
        reg = <0x44b00000 0x1000>;
        clocks = <&spi_clk>;
-       #pwm-cells = <2>;
+       #pwm-cells = <3>;
     };