The binding dictates using 3 pwm-cells. Adhere to that.
This fixes the following dtbs_check warnings:
	arch/arm/boot/dts/nxp/imx/imx53-ppd.dtb: pwm@
53fb4000: #pwm-cells:0:0: 3 was expected
		from schema : http://devicetree.org/schemas/pwm/imx-pwm.yaml#
	arch/arm/boot/dts/nxp/imx/imx53-ppd.dtb: pwm@
53fb8000: #pwm-cells:0:0: 3 was expected
		from schema : http://devicetree.org/schemas/pwm/imx-pwm.yaml#
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
 
        pwm_bl: backlight {
                compatible = "pwm-backlight";
-               pwms = <&pwm2 0 50000>;
+               pwms = <&pwm2 0 50000 0>;
                brightness-levels = <0 2 5 7 10 12 15 17 20 22 25 28 30 33 35
                                     38 40 43 45 48 51 53 56 58 61 63 66 68 71
                                     73 76 79 81 84 86 89 91 94 96 99 102 104
 
                led-1 {
                        label = "alarm-brightness";
-                       pwms = <&pwm1 0 100000>;
+                       pwms = <&pwm1 0 100000 0>;
                        max-brightness = <255>;
                };
        };
 };
 
 &pwm1 {
-       #pwm-cells = <2>;
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_pwm1>;
        status = "okay";
 };
 
 &pwm2 {
-       #pwm-cells = <2>;
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_pwm2>;
        status = "okay";