ARM: dts: imx6q-kp: Use #pwm-cells = <3> for imx27-pwm device

The binding dictates using 3 pwm-cells. Adhere to that.

This fixes the following dtbs_check warnings:

	arch/arm/boot/dts/nxp/imx/imx6q-kp-tpc.dtb: pwm@2080000: #pwm-cells:0:0: 3 was expected
		from schema : http://devicetree.org/schemas/pwm/imx-pwm.yaml#
	arch/arm/boot/dts/nxp/imx/imx6q-kp-tpc.dtb: pwm@2084000: #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>

arch/arm/boot/dts/nxp/imx/imx6q-kp.dtsi

@@ -15,7 +15,7 @@
 / {
 	backlight_lcd: backlight-lcd {
 		compatible = "pwm-backlight";
-		pwms = <&pwm1 0 5000000>;
+		pwms = <&pwm1 0 5000000 0>;
 		brightness-levels = <0 255>;
 		num-interpolated-steps = <255>;
 		default-brightness-level = <250>;
@@ -23,7 +23,7 @@ backlight_lcd: backlight-lcd {
 
 	beeper {
 		compatible = "pwm-beeper";
-		pwms = <&pwm2 0 500000>;
+		pwms = <&pwm2 0 500000 0>;
 	};
 
 	lcd_display: display {
@@ -378,14 +378,12 @@ MX6QDL_PAD_SD4_DAT7__SD4_DATA7		0x17059
 };
 
 &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";