audio: rename virtualizer stage to spatializer

Use audio spatializer and spatialization instead of
virtualizer stage to reflect the name chosen for public APIs.

Bug: 188502620
Test: make
Change-Id: I7974c5b159722efd795e0b0b79ddbb0658c52034
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 17ecf21..a77a27d 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -2569,10 +2569,10 @@
             return thread;
         } else {
             sp<PlaybackThread> thread;
-            //TODO: b/193496180 use virtualizer stage flag at audio HAL when available
+            //TODO: b/193496180 use spatializer flag at audio HAL when available
             if (flags == (audio_output_flags_t)(AUDIO_OUTPUT_FLAG_FAST
                                                     | AUDIO_OUTPUT_FLAG_DEEP_BUFFER)) {
-                thread = new VirtualizerStageThread(this, outputStream, *output,
+                thread = new SpatializerThread(this, outputStream, *output,
                                                     mSystemReady, mixerConfig);
                 ALOGD("openOutput_l() created virtualizer output: ID %d thread %p",
                       *output, thread.get());