hal: apply bt-sco-wb samplerate mixer

- BTSCO WB sample rate mixer control applied after AFE port opened.
  This results sample rate mismatch and voice call over BT SCO WB
  does not work
- Fix by apply the mixer control before AFE port opened

Change-Id: I7efa0db9a24d307780bde03032313ad1f454d6ac
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index 3b736f0..fea43a3 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -1312,6 +1312,11 @@
     if (ret >= 0) {
         str_parms_del(parms, AUDIO_PARAMETER_KEY_BTSCO);
         my_data->btsco_sample_rate = val;
+        if (val == SAMPLE_RATE_16KHZ) {
+            audio_route_apply_path(my_data->adev->audio_route,
+                                   "bt-sco-wb-samplerate");
+            audio_route_update_mixer(my_data->adev->audio_route);
+        }
     }
 
     ret = str_parms_get_int(parms, AUDIO_PARAMETER_KEY_SLOWTALK, &val);