sound - haswell / ALC283 - Acer C720 support

sound - haswell / ALC283 - Acer C720 support

* Get headphone auto-sensing and speaker/headphone selection changes working.
  I couldn't figure out how to do it with the hpredir mechanism so I added
  a new field, w->senseredir, which tells the driver to also mess around
  with mixer selections.

  In the case of the Acer C720 nid 33 (the headphone) has two mixer
  selections, allowing either DMA channel to be selected while nid 20
  (the speaker) only has one.  The default selection winds up being
  wrong.  The senseredir field allows the sense mechanism to determine
  the correct selection and do change the active selection.

* WARNING!  We currently do not parse the acer out-of-band config data
  to figure out the headphone sense.