ARM: dts: s3c24xx: fix number of PWM cells

The PWM has only three cells, not four, as pointed out by dtschema:

  timer@51000000: #pwm-cells:0:0: 3 was expected
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200907183313.29234-8-krzk@kernel.org

arch/arm/boot/dts/s3c24xx.dtsi

@@ -43,7 +43,7 @@ timer@51000000 {
 		compatible = "samsung,s3c2410-pwm";
 		reg = <0x51000000 0x1000>;
 		interrupts = <0 0 10 3>, <0 0 11 3>, <0 0 12 3>, <0 0 13 3>, <0 0 14 3>;
-		#pwm-cells = <4>;
+		#pwm-cells = <3>;
 	};
 
 	uart0: serial@50000000 {