hal: Fix aanc sequence during voice call

When aanc is enabled during voice call, TX and RX  path mixer
controls are issued back to back, this causes the codec path to be
enabled from TX to RX as the internal loopback for aanc exists. Due
to enabling this path, mute is observed on handset. This issue
is fixed by treating aanc as special usecase and changing the enable
and disable sequence of aanc mixer controls.

Change-Id: I305156cb80e6faf35bd6ab4fc089740ffa847f43
diff --git a/hal/msm8916/platform.c b/hal/msm8916/platform.c
index a5cc804..ab8c6f0 100644
--- a/hal/msm8916/platform.c
+++ b/hal/msm8916/platform.c
@@ -5622,6 +5622,14 @@
     return 0;
 }
 
+void platform_update_aanc_path(struct audio_device *adev __unused,
+                               snd_device_t out_snd_device __unused,
+                               bool enable __unused,
+                               char *str __unused)
+{
+   return;
+}
+
 bool platform_check_codec_dsd_support(void *platform __unused)
 {
     return false;