media: dt-bindings: qcom,sc7180-venus: document OPP table

Venus on Qualcomm SC7180 uses Operating Performance Points (both in DTS
and driver):

  sc7180-idp.dtb: video-codec@aa00000: Unevaluated properties are not allowed ('operating-points-v2', 'opp-table' were unexpected)
Signed-off-by: NKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@kernel.org>

Documentation/devicetree/bindings/media/qcom,sc7180-venus.yaml

@@ -56,6 +56,10 @@ properties:
       - const: video-mem
       - const: cpu-cfg
 
+  operating-points-v2: true
+  opp-table:
+    type: object
+
   video-decoder:
     type: object