ARM: tegra: gr3d is not backwards-compatible

The instantiation of gr3d in Tegra114 is not backwards-compatible with
the version found on earlier chips. Remove the misleading compatible
string.
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra114.dtsi

@@ -46,7 +46,7 @@ gr2d@54140000 {
 		};
 
 		gr3d@54180000 {
-			compatible = "nvidia,tegra114-gr3d", "nvidia,tegra20-gr3d";
+			compatible = "nvidia,tegra114-gr3d";
 			reg = <0x54180000 0x00040000>;
 			clocks = <&tegra_car TEGRA114_CLK_GR3D>;
 			resets = <&tegra_car 24>;