audio: Add support for bluetooth voice calls

Change-Id: Ic63b7c09ed7401ab72824a406db333e3fbce780b
diff --git a/audio/voice.h b/audio/voice.h
index 10f0fef..c89a372 100644
--- a/audio/voice.h
+++ b/audio/voice.h
@@ -25,6 +25,9 @@
     struct pcm *pcm_voice_rx;
     struct pcm *pcm_voice_tx;
 
+    struct pcm *pcm_sco_rx;
+    struct pcm *pcm_sco_tx;
+
     bool wb_amr;
     bool two_mic_control;
     bool two_mic_disabled;
@@ -41,6 +44,8 @@
 void set_voice_session_audio_path(struct voice_session *session);
 void set_voice_session_mic_mute(struct voice_session *session, bool state);
 
+void start_voice_session_bt_sco(struct voice_session *session);
+
 bool voice_session_uses_twomic(struct voice_session *session);
 bool voice_session_uses_wideband(struct voice_session *session);