arm64: dts: rockchip: increase mcu frequency to 97mhz for rk3399

mcu run at 97MHz to reduce lpddr4 scale frequency elapsed time

Change-Id: Ie2805eaf0d902c9531819217d05a86775d85f809
Signed-off-by: CanYang He <hcy@rock-chips.com>

Author: CanYang He

arch/arm64/boot/dts/rockchip/rk3399.dtsi

@@ -1451,8 +1451,8 @@
 		reg = <0x0 0xff750000 0x0 0x1000>;
 		#clock-cells = <1>;
 		#reset-cells = <1>;
-		assigned-clocks = <&pmucru PLL_PPLL>;
-		assigned-clock-rates = <676000000>;
+		assigned-clocks = <&pmucru PLL_PPLL>, <&pmucru FCLK_CM0S_SRC_PMU>;
+		assigned-clock-rates = <676000000>, <97000000>;
 	};
 
 	cru: clock-controller@ff760000 {