hal: Fix voice session setup failure

Sometimes no RTP packets transferred in VoLTE call on headset.
Voice call path setup is failed due to no backends enabled.
This happens when routing is triggered on combo device for
primary output and mode is MODE_IN_CALL at that time.
Fix this issue by selecting proper device based on in call
information.

CRs-Fixed: 859796
Change-Id: I9a5a6b9296d168e9292b94fda147491ee35c0edd
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index 26c676a..9da99be 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -2020,7 +2020,7 @@
         goto exit;
     }
 
-    if (popcount(devices) == 2) {
+    if (popcount(devices) == 2 && !voice_is_in_call(adev)) {
         if (devices == (AUDIO_DEVICE_OUT_WIRED_HEADPHONE |
                         AUDIO_DEVICE_OUT_SPEAKER)) {
             if (my_data->external_spk_1)