This register exists only pre GEN5, but atm we also access it on
VLV/BXT/CHV. Prevent accessing it on these latter platforms.
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>