drm/msm/dpu: move max clock decision to dpu_kms.

dpu_core_perf should not make decisions on the maximum possible core
clock rate. Pass the value from dpu_kms_hw_init() and drop handling of
core_clk from dpu_core_perf.c

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/550201/
Link: https://lore.kernel.org/r/20230730010102.350713-10-dmitry.baryshkov@linaro.org