wasapi: report volume/mute (refs #6880, refs #7203)

This is a temporary hack to make the volume controls mostly work until
Windows volume notifications are correctly implemented.

modules/audio_output/wasapi.c

@@ -207,6 +207,8 @@ static int SimpleVolumeSet(audio_output_t *aout, float vol)
     hr = ISimpleAudioVolume_SetMasterVolume(sys->volume.simple, vol, NULL);
     if (FAILED(hr))
         msg_Warn(aout, "cannot set session volume (error 0x%lx)", hr);
+    else /* Hack until volume notifications implemented: */
+        aout_VolumeReport(aout, vol);
     Leave();
     return FAILED(hr) ? -1 : 0;
 }
@@ -221,6 +223,8 @@ static int SimpleMuteSet(audio_output_t *aout, bool mute)
     hr = ISimpleAudioVolume_SetMute(sys->volume.simple, mute, NULL);
     if (FAILED(hr))
         msg_Warn(aout, "cannot mute session (error 0x%lx)", hr);
+    else /* Hack until volume notifications implemented: */
+        aout_MuteReport(aout, mute);
     Leave();
     return FAILED(hr) ? -1 : 0;
 }