dt-bindings: display: msm: dp-controller: document SM6350 compatible

Add the compatible string for the DisplayPort controller on SM6350 which
is compatible with the one on SM8350.

Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Luca Weiss <[e-mail]>
Patchwork: https://patchwork.freedesktop.org/patch/585469/
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Baryshkov <[e-mail]>

Documentation/devicetree/bindings/display/msm/dp-controller.yaml

···
           - qcom,sm8650-dp
       - items:
           - enum:
+              - qcom,sm6350-dp
               - qcom,sm8150-dp
               - qcom,sm8250-dp
               - qcom,sm8450-dp