drm/msm/dpu: Clear perf params before calculating bw

To prevent incorrect BW calculation, zero out dpu_core_perf_params
before it is passed into dpu_core_perf_aggregate().

Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Fixes: 795aef6f ("drm/msm/dpu: remove duplicate code calculating sum of bandwidths")
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/641278/


Signed-off-by: Rob Clark <robdclark@chromium.org>