arm64: tegra: Add IOMMU node to GM20B on Tegra210

The operating system driver can take advantage of the IOMMU to remove
the need for physically contiguous memory buffers.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm64/boot/dts/nvidia/tegra210.dtsi

@@ -231,6 +231,9 @@
 		clock-names = "gpu", "pwr", "ref";
 		resets = <&tegra_car 184>;
 		reset-names = "gpu";
+
+		iommus = <&mc TEGRA_SWGROUP_GPU>;
+
 		status = "disabled";
 	};