klte-common: Increase gain for mixer path "vr-main-mic"

* Recordings with the Voice Recorder app were very low, increase to
  match that of stock mixer_paths.xml from T-Mobiles NH5 release.

Change-Id: Ia0d036e5c8bad00a8ae99e93b4ce8a60cddb34e1
Merge remote-tracking branch 'cm/cm-11.0' into HEAD