drm/msm/dpu: Drop unused get_scaler_ver callback from SSPP

This pointer callback is never used and should be removed.

Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
[DB: dropped the helpers completely, which are unused now]
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/570096/
Link: https://lore.kernel.org/r/20231201234234.2065610-3-dmitry.baryshkov@linaro.org