drm/i915/pvc: Add recommended MMIO setting

drm/i915/pvc: Add recommended MMIO setting

As with past platforms, the bspec's performance tuning guide provides
recommended MMIO settings.  Although not technically "workarounds" we
apply these through the workaround framework to ensure that they're
re-applied at the proper times (e.g., on engine resets) and that any
conflicts with real workarounds are flagged.

Bspec: 72161
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220613165314.862029-1-matthew.d.roper@intel.com