drm/i915: store the peak bw per QGV point

In MTL onwards, pcode locks the GV point based on the peak BW
of a QGV point. So store the peak BW of all the QGV points.

v2: use DIV_ROUND_CLOSEST() for the peakBW calculation

Bspec: 64636

Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230606093509.221709-4-vinod.govindapillai@intel.com