rockchip: dts: evb-rk3399: correct pwm3 polarity

The pwm3 on evb-rk3399 is used for pwm regulator, need to invert
the polarity to make it work correctly.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/arm/dts/rk3399-evb.dts

@@ -20,7 +20,7 @@
 
 	vdd_center: vdd-center {
 		compatible = "pwm-regulator";
-		pwms = <&pwm3 0 25000 0>;
+		pwms = <&pwm3 0 25000 1>;
 		regulator-name = "vdd_center";
 		regulator-min-microvolt = <800000>;
 		regulator-max-microvolt = <1400000>;