drm/i915/pvc: Annotate two more workaround/tuning registers as MCR

XEHPC_LNCFMISCCFGREG0 and XEHPC_L3SCRUB are both in MCR register ranges
on PVC (with HALFBSLICE and L3BANK replication respectively), so they
should be explicitly declared as MCR registers and use MCR-aware
workaround handlers.

The workarounds/tuning settings should still be applied properly on PVC
even without the MCR annotation, but readback verification on
CONFIG_DRM_I915_DEBUG_GEM builds could potentitally give false positive
"workaround lost on load" warnings on parts fused such that a unicast
read targets a terminated register instance.

Fixes: a9e69428

 ("drm/i915: Define MCR registers explicitly")
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230201222831.608281-1-matthew.d.roper@intel.com