drm/msm/dpu: drop enum dpu_core_perf_data_bus_id

Drop the leftover of bus-client -> interconnect conversion, the enum
dpu_core_perf_data_bus_id.

Fixes: cb88482e ("drm/msm/dpu: clean up references of DPU custom bus scaling")
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/550194/
Link: https://lore.kernel.org/r/20230730010102.350713-2-dmitry.baryshkov@linaro.org