drm/msm/dpu: drop dpu_encoder_phys_ops::late_register()

drm/msm/dpu: drop dpu_encoder_phys_ops::late_register()

This callback has been unused since the driver being added. Drop it now.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/538302/
Link: https://lore.kernel.org/r/20230521192230.9747-1-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>