This change fixes the following compiler error with rpcs3 project.
``` rpcs3/Emu/Audio/XAudio2/XAudio2Backend.cpp: In member function 'virtual bool XAudio2Backend::Open(std::string_view, AudioFreq, AudioSampleSize, AudioChannelCnt)': rpcs3/Emu/Audio/XAudio2/XAudio2Backend.cpp:244:66: error: no matching function for call to 'IXAudio2::CreateMasteringVoice(IXAudio2MasteringVoice**, int, int, int, const wchar_t*)' 244 | if (HRESULT hr = m_xaudio2_instance->CreateMasteringVoice(&m_master_voice, 0, 0, 0, utf8_to_wchar(use_default_device ? selected_dev_id : dev_id).c_str()); FAILED(hr)) | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from rpcs3/Emu/Audio/XAudio2/XAudio2Backend.h:14, from rpcs3/Emu/Audio/XAudio2/XAudio2Backend.cpp:11: xaudio2.h:1571:39: note: candidate: 'virtual HRESULT IXAudio2::CreateMasteringVoice(IXAudio2MasteringVoice**, UINT32, UINT32, UINT32, LPCWSTR, const XAUDIO2_EFFECT_CHAIN*, AUDIO_STREAM_CATEGORY)' 1571 | virtual HRESULT STDMETHODCALLTYPE CreateMasteringVoice( | ^~~~~~~~~~~~~~~~~~~~ xaudio2.h:1571:39: note: candidate expects 7 arguments, 5 provided ```