Adapt platforms to AudioServer refactoring

Fixes compilation on Windows and likely other platforms (at least
as far as AudioServer changes were concerned), though they were
not tested.

drivers/xaudio2/audio_driver_xaudio2.h

@@ -29,8 +29,7 @@
 #ifndef AUDIO_DRIVER_XAUDIO2_H
 #define AUDIO_DRIVER_XAUDIO2_H
 
-#include "servers/audio/audio_server_sw.h"
-
+#include "servers/audio_server.h"
 #include "core/os/thread.h"
 #include "core/os/mutex.h"
 
@@ -72,7 +71,7 @@ class AudioDriverXAudio2 : public AudioDriver {
 	int buffer_size;
 
 	unsigned int mix_rate;
-	OutputFormat output_format;
+	SpeakerMode speaker_mode;
 
 	int channels;
 
@@ -96,7 +95,7 @@ public:
 	virtual Error init();
 	virtual void start();
 	virtual int get_mix_rate() const;
-	virtual OutputFormat get_output_format() const;
+	virtual SpeakerMode get_speaker_mode() const;
 	virtual float get_latency();
 	virtual void lock();
 	virtual void unlock();