AudioStream: Replace buffer queue with ring buffer

Should achieve a decent overall minimum latency reduction.

src/core/host_interface.h

@@ -38,8 +38,7 @@ public:
   {
     AUDIO_SAMPLE_RATE = 44100,
     AUDIO_CHANNELS = 2,
-    DEFAULT_AUDIO_BUFFER_SIZE = 2048,
-    DEFAULT_AUDIO_BUFFER_COUNT = 4
+    DEFAULT_AUDIO_BUFFER_SIZE = 2048
   };
 
   struct SaveStateInfo