faudio: add gui code for selecting driver

Add code to swtich to faudio api when the option is selected in the
config dialog in guiinit.cpp.

src/wx/guiinit.cpp

@@ -3441,6 +3441,10 @@ bool MainFrame::BindControls()
             audapi_rb("XAudio2", AUD_XAUDIO2);
 #if !defined(__WXMSW__) || defined(NO_XAUDIO2)
             rb->Hide();
+#endif
+            audapi_rb("Faudio", AUD_FAUDIO);
+#ifdef NO_FAUDIO
+            rb->Hide();
 #endif
             sound_config_handler.dev = SafeXRCCTRL<wxChoice>(d, "Device");
             sound_config_handler.dev->SetValidator(SoundConfigLoad());