media: dt-bindings: qcom,sc7280-venus: document OPP table

Venus on Qualcomm SC7280 uses Operating Performance Points (both in DTS
and driver):

  sc7280-crd-r3.dtb: video-codec@aa00000: Unevaluated properties are not allowed ('operating-points-v2', 'opp-table' were unexpected)
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Documentation/devicetree/bindings/media/qcom,sc7280-venus.yaml

@@ -53,6 +53,10 @@ properties:
       - const: cpu-cfg
       - const: video-mem
 
+  operating-points-v2: true
+  opp-table:
+    type: object
+
   video-decoder:
     type: object