alsa_sound: Add support for "Voice Earpiece Extra Gain" mode

Uses "Voice Earpiece Extra Gain" mode instead of "Voice Earpiece" during
voice calls when persist.audio.voc_ep.xgain=1.

Change-Id: I9f00a81687fa9605c68308a74e0ffaaea7e698fc
hal: Use correct path for audio_defs header

Change-Id: I10f0e842e2ffb9ed9a67a2f62f93bd47cb2f28ad
audio: Use direct project pathmap

Change-Id: Id42a7dad4e9b8aa207c6991fa37e1b4e92c5db9c