Spatializer: Disable head tracking for stereo spatialization

Do not enable head tracking if all the spatialized tracks are stereo.

Flag: EXEMPT bugfix
Test: manual spatial audio tests
Test: atest spatializer_tests
Bug: 356953811
Change-Id: I75e2cb63ee4c5c5bfba628802198d056fd30e216
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index 739e201..90d7709 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -6358,10 +6358,11 @@
     // mode is not requested.
 
     if (config != nullptr && *config != AUDIO_CONFIG_INITIALIZER) {
-        static const bool stereo_spatialization_enabled =
+        static const bool stereo_spatialization_prop_enabled =
                 property_get_bool("ro.audio.stereo_spatialization_enabled", false);
         const bool channel_mask_spatialized =
-                (stereo_spatialization_enabled && com_android_media_audio_stereo_spatialization())
+                (stereo_spatialization_prop_enabled
+                        && com_android_media_audio_stereo_spatialization())
                 ? audio_channel_mask_contains_stereo(config->channel_mask)
                 : audio_is_channel_mask_spatialized(config->channel_mask);
         if (!channel_mask_spatialized) {