arm64: dts: rockchip: rk3368-xikp: Update display clock frequency for panel

Target pixel clock rate for refresh rate @60 Hz
	= 1341 * 1981 * 60 = 159391260 Hz ~ 159 MHz

Change-Id: Ia018ad3c1a34c48e676f9b63b06e7a2f1cb658f2
Signed-off-by: Wyon Bi <bivvy.bi@rock-chips.com>

Author: bivvy

arch/arm64/boot/dts/rockchip/rk3368-xikp.dts

@@ -779,7 +779,7 @@
 			native-mode = <&timing0>;
 
 			timing0: timing0 {
-				clock-frequency = <145000000>;
+				clock-frequency = <159000000>;
 				hactive = <1200>;
 				vactive = <1920>;
 				hback-porch = <60>;