arm64: dts: rockchip: add 'gpu_power_model' feature with DDK r14 for linux

Since the mali.ko is *not* upgraded by userspace, rk3399 linux hope keep
mali driver version is the same with userspace.

Change-Id: Id5af615f1f7b0c95587bc5faeeeff35251797e1a
Signed-off-by: Zhen Chen <chenzhen@rock-chips.com>

Author: Zhen Chen

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

@@ -152,6 +152,15 @@
 	};
 };
 
+/* HACK: keep MALI version on linux */
+&gpu_power_model {
+	// for DDK r14.
+	voltage = <900>;
+	frequency = <500>;
+	static-power = <300>;
+	dynamic-power = <396>;
+};
+
 &pvtm {
 	status = "okay";
 };