drm/msm/dp: Add DisplayPort controller for SM8350

The Qualcomm SM8350 platform comes with a single DisplayPort controller,
add support for this in the DisplayPort driver.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20211228045934.1524865-1-bjorn.andersson@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>