arm64: dts: freescale: imx8-ss-dma: Fix #pwm-cells

i.MX8QXP supports inverted PWM output, thus #pwm-cells needs to be set
to 3.

Fixes: f1d6a6b ("arm64: dts: imx8qxp: add adma_pwm in adma")
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: tq-steina

arch/arm64/boot/dts/freescale/imx8-ss-dma.dtsi

@@ -149,7 +149,7 @@ dma_subsys: bus@5a000000 {
 		clock-names = "ipg", "per";
 		assigned-clocks = <&clk IMX_SC_R_LCD_0_PWM_0 IMX_SC_PM_CLK_PER>;
 		assigned-clock-rates = <24000000>;
-		#pwm-cells = <2>;
+		#pwm-cells = <3>;
 		power-domains = <&pd IMX_SC_R_LCD_0_PWM_0>;
 	};