arm64: dts: rockchip: px30: modify voltage for gpu 200MHz and 300Mhz

Change-Id: Ifbd3117d3999b322951df458a12cfe488954803d
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>

Author: finley1226

arch/arm64/boot/dts/rockchip/px30.dtsi

@@ -1166,11 +1166,11 @@
 
 		opp-200000000 {
 			opp-hz = /bits/ 64 <200000000>;
-			opp-microvolt = <1000000>;
+			opp-microvolt = <950000>;
 		};
 		opp-300000000 {
 			opp-hz = /bits/ 64 <300000000>;
-			opp-microvolt = <1000000>;
+			opp-microvolt = <950000>;
 		};
 		opp-400000000 {
 			opp-hz = /bits/ 64 <400000000>;