drm/i915: More PVC+DG2 workarounds

A new PVC+DG2 workaround has appeared recently:
 - Wa_16015675438

And a couple existing DG2 workarounds have been extended to PVC:
 - Wa_14015795083
 - Wa_18018781329

Note that Wa_16015675438 asks us to program a register that is in the
0x2xxx range typically associated with the RCS engine, even though PVC
does not have an RCS.  By default the GuC will think we've made a
mistake and throw an exception when it sees this register on a CCS
engine's save/restore list, so we need to pass an extra GuC control flag
to tell it that this is expected and not a problem.

Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Signed-off-by: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220608005108.3717895-1-matthew.d.roper@intel.com