drm/msm/dpu: drop the dpu_core_perf_crtc_update()'s stop_req param

The stop_req is true only in the dpu_crtc_disable() case, when
crtc->enable has already been set to false. This renders the stop_req
argument useless. Remove it completely.

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/550206/
Link: https://lore.kernel.org/r/20230730010102.350713-6-dmitry.baryshkov@linaro.org