hal: make event enum value to be uniform with sound trigger hal

Insert a new enum type in audio event type definition, this is
to keep the event type reported to sound trigger HAL to be
consistent with audio HAL.

Change-Id: Id6024cd22752665da91f0db97217df08e4091dfe
diff --git a/hal/audio_extn/soundtrigger.c b/hal/audio_extn/soundtrigger.c
index c69b352..1c98103 100644
--- a/hal/audio_extn/soundtrigger.c
+++ b/hal/audio_extn/soundtrigger.c
@@ -79,6 +79,7 @@
     AUDIO_EVENT_SVA_EXEC_MODE_STATUS,
     AUDIO_EVENT_CAPTURE_STREAM_INACTIVE,
     AUDIO_EVENT_CAPTURE_STREAM_ACTIVE,
+    AUDIO_EVENT_BATTERY_STATUS_CHANGED,
     AUDIO_EVENT_GET_PARAM
 } audio_event_type_t;