ARM: dts: msm: Override GPU speed bin 2 for MSM8996Pro

In DRM driver gpu clock don't change. override the initial gpu clock to
maximal value to ensure the performance in auto system.

Change-Id: I95515aedfb7b6e462d693cc5ae945ac21fcba7b8
Signed-off-by: Kasin Li <donglil@codeaurora.org>

arch/arm/boot/dts/qcom/msm8996pro-auto.dtsi

@@ -466,5 +466,11 @@
 		qcom,gpu-pwrlevels-0 {
 			qcom,initial-pwrlevel = <1>;
 		};
+
+		qcom,gpu-pwrlevels-2 {
+			qcom,initial-pwrlevel = <2>;
+
+		};
+
 	};
 };