hal: add standalone flag to report event to sthal

Add a new flag to indicate that if there is an active
voice call ongoing, then correct usecase type can be
populated before reporting concurrency event to sthal.
This also reverts f5f32107dd0a423c89385ee2310c1565d49ce69d.

Change-Id: I7044e54d5a8a95bf8cebe2e8198f51f2be1ea35c
diff --git a/hal/audio_extn/soundtrigger.c b/hal/audio_extn/soundtrigger.c
index b3df579..d7bbb2f 100644
--- a/hal/audio_extn/soundtrigger.c
+++ b/hal/audio_extn/soundtrigger.c
@@ -561,7 +561,7 @@
     struct stream_in *active_input = adev_get_active_input(st_dev->adev);
     audio_source_t  source = (active_input == NULL) ?
                                AUDIO_SOURCE_DEFAULT : active_input->source;
-    if (voice_is_in_call(st_dev->adev)) {
+    if (voice_is_uc_active(st_dev->adev)) {
         ev_info.u.usecase.type = USECASE_TYPE_VOICE_CALL;
     } else if ((st_dev->adev->mode == AUDIO_MODE_IN_COMMUNICATION ||
                 source == AUDIO_SOURCE_VOICE_COMMUNICATION) &&