SoundStream: remove unused m_muted and IsMuted

Source/Core/AudioCommon/AlsaSoundStream.cpp

@@ -80,7 +80,6 @@ void AlsaSound::SoundLoop()
 
 void AlsaSound::Clear(bool muted)
 {
-  m_muted = muted;
   m_thread_status.store(muted ? ALSAThreadStatus::PAUSED : ALSAThreadStatus::RUNNING);
   cv.notify_one();  // Notify thread that status has changed
 }

Source/Core/AudioCommon/NullSoundStream.cpp

@@ -35,11 +35,6 @@ void NullSound::Update()
   m_mixer->Mix(m_realtime_buffer.data(), (unsigned int)num_samples_to_render);
 }
 
-void NullSound::Clear(bool mute)
-{
-  m_muted = mute;
-}
-
 void NullSound::Stop()
 {
 }

Source/Core/AudioCommon/NullSoundStream.h

@@ -14,7 +14,6 @@ public:
   void SoundLoop() override;
   void SetVolume(int volume) override;
   void Stop() override;
-  void Clear(bool mute) override;
   void Update() override;
 
   static bool isValid() { return true; }

Source/Core/AudioCommon/OpenALStream.cpp

@@ -163,9 +163,7 @@ void OpenALStream::Update()
 
 void OpenALStream::Clear(bool mute)
 {
-  m_muted = mute;
-
-  if (m_muted)
+  if (mute)
   {
     palSourceStop(m_source);
   }

Source/Core/AudioCommon/SoundStream.h

@@ -13,10 +13,9 @@ class SoundStream
 {
 protected:
   std::unique_ptr<Mixer> m_mixer;
-  bool m_muted;
 
 public:
-  SoundStream() : m_mixer(new Mixer(48000)), m_muted(false) {}
+  SoundStream() : m_mixer(new Mixer(48000)) {}
   virtual ~SoundStream() {}
   static bool isValid() { return false; }
   Mixer* GetMixer() const { return m_mixer.get(); }
@@ -25,6 +24,5 @@ public:
   virtual void SoundLoop() {}
   virtual void Stop() {}
   virtual void Update() {}
-  virtual void Clear(bool mute) { m_muted = mute; }
-  bool IsMuted() const { return m_muted; }
+  virtual void Clear(bool mute) {}
 };

Source/Core/AudioCommon/XAudio2Stream.cpp

@@ -212,11 +212,9 @@ void XAudio2::SetVolume(int volume)
 
 void XAudio2::Clear(bool mute)
 {
-  m_muted = mute;
-
   if (m_voice_context)
   {
-    if (m_muted)
+    if (mute)
       m_voice_context->Stop();
     else
       m_voice_context->Play();

Source/Core/AudioCommon/XAudio2_7Stream.cpp

@@ -200,11 +200,9 @@ void XAudio2_7::SetVolume(int volume)
 
 void XAudio2_7::Clear(bool mute)
 {
-  m_muted = mute;
-
   if (m_voice_context)
   {
-    if (m_muted)
+    if (mute)
       m_voice_context->Stop();
     else
       m_voice_context->Play();