media: dt: bindings: tegra-vde: Document new optional IOMMU property

All NVIDIA Tegra SoC generations provide IOMMU support for the video
decoder engine. Document new optional device-tree property that connects
VDE with the IOMMU provider.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/devicetree/bindings/media/nvidia,tegra-vde.txt

@@ -35,6 +35,7 @@ Optional properties:
 - resets : Must contain an entry for each entry in reset-names.
 - reset-names : Must include the following entries:
   - mc
+- iommus: Must contain phandle to the IOMMU device node.
 
 Example:
 
@@ -59,4 +60,5 @@ video-codec@6001a000 {
 	clocks = <&tegra_car TEGRA20_CLK_VDE>;
 	reset-names = "vde", "mc";
 	resets = <&tegra_car 61>, <&mc TEGRA20_MC_RESET_VDE>;
+	iommus = <&mc TEGRA_SWGROUP_VDE>;
 };