dt-bindings: tegra: Document P3971-0089+P3834-0008 Platform

This is an engineering reference platform for the Tegra264 SoC.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250507143802.1230919-4-thierry.reding@gmail.com
Signed-off-by: Thierry Reding <treding@nvidia.com>

Author: thierryreding

Documentation/devicetree/bindings/arm/tegra.yaml

@@ -242,5 +242,10 @@ properties:
           - const: nvidia,p3768-0000+p3767-0005
           - const: nvidia,p3767-0005
           - const: nvidia,tegra234
+      - description: NVIDIA P3971-0089+P3834-0008 Engineering Reference Platform
+        items:
+          - const: nvidia,p3971-0089+p3834-0008
+          - const: nvidia,p3834-0008
+          - const: nvidia,tegra264
 
 additionalProperties: true