This workaround is listed for CHV, but not for BDW. However BSpec notes
that on BDW CSunit clock gating is always disabled irrespective of the
relevant bit in the GEN6_UGCTL1 registers. For CHV however, such text
is not present in BSpec, so it seems safer to just set the bit.
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>