v2:
- Make the condition to select between SKL and BXT consistent with the
  corresponding condition in init_workarounds_ring (Nick)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NNick Hoath <nicholas.hoath@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>