UI: Remove unused function from volume control

UI/volume-control.cpp

@@ -57,17 +57,6 @@ void VolControl::VolumeChanged()
 	updateText();
 }
 
-void VolControl::VolumeLevel(float mag, float peak, float peakHold, bool muted)
-{
-	if (muted) {
-		mag = 0.0f;
-		peak = 0.0f;
-		peakHold = 0.0f;
-	}
-
-	volMeter->setLevels(mag, peak, peakHold);
-}
-
 void VolControl::VolumeMuted(bool muted)
 {
 	if (mute->isChecked() != muted)

UI/volume-control.hpp

@@ -94,7 +94,6 @@ private:
 private slots:
 	void VolumeChanged();
 	void VolumeMuted(bool muted);
-	void VolumeLevel(float mag, float peak, float peakHold, bool muted);
 
 	void SetMuted(bool checked);
 	void SliderChanged(int vol);