drm/i915/icl: WaDisableImprovedTdlClkGating

Revert to the legacy implementation.

v2: GEN7_ROW_CHICKEN2 is masked
v3:
  - Rebased
  - Renamed to Wa_2006611047
  - A0 and B0 only
v4:
  - Add spaces around '<<' (and fix the surrounding code as well)
  - Mark the WA as pre-prod
v5: Rebased on top of the WA refactoring
v6: Added References (Mika)
v7: Fixed in B0

References: HSDES#2006611047
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1527285939-20113-2-git-send-email-oscar.mateo@intel.com