dt-bindings: dma: Add Tegra264 compatible string

Document the compatible string used for the GPCDMA controller on
Tegra264.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250507143802.1230919-2-thierry.reding@gmail.com
Signed-off-by: Thierry Reding <treding@nvidia.com>

Author: thierryreding

Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml

@@ -24,6 +24,7 @@ properties:
       - const: nvidia,tegra186-gpcdma
       - items:
           - enum:
+              - nvidia,tegra264-gpcdma
               - nvidia,tegra234-gpcdma
               - nvidia,tegra194-gpcdma
           - const: nvidia,tegra186-gpcdma