drm/i915/mtl: Update memory bandwidth parameters

Like ADL_P, Meteorlake has different memory characteristics from
past platforms. Update the values used by our memory bandwidth
calculations accordingly.

Bspec: 64631

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220818234202.451742-17-radhakrishna.sripada@intel.com