Let's clean this a bit

v2: Rebase after other Mika's patch that removed some BDW production workarounds.
v3: Removed stepping info.
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>