On HSW the LP1,LP2,LP3 levels are either 1,2,3 or 1,3,4. We make the
conversion from LPn to to the level at one point current. Later we're
going to do it in a few places, so move it to a separate function.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>