chore: simplified audio callback

frontends/sdl/src/main.rs

@@ -488,21 +488,6 @@ impl Emulator {
                     }
                 }
 
-                // in case there's pending audio data available in the emulator
-                // we must handle it, sending it to the audio callback
-                if self.system.audio_buffer().is_empty() {
-                    if let Some(audio) = self.audio.as_mut() {
-                        let audio_buffer = self
-                            .system
-                            .audio_buffer()
-                            .iter()
-                            .map(|v| *v as f32 / VOLUME)
-                            .collect::<Vec<f32>>();
-                        audio.device.queue_audio(&audio_buffer).unwrap();
-                    }
-                    self.system.clear_audio_buffer();
-                }
-
                 // in case there's at least one new frame that was drawn during
                 // during the current tick, then we need to flush it to the canvas,
                 // this separation between texture creation and canvas flush prevents