alsa_sound: use "Voice Speaker" instead of "Speaker" when in calls

This change enables the use of "Voice Speaker" usecase when in-call,
instead of "Speaker". This permit us to control then volume of
speakerphone, without change normal speaker volume.

Change-Id: Ied491fc972124a31d53c25743728a407906e8920
Merge remote-tracking branch 'upstream/cm-10.1' into cm-10.1