samv7:tone_alarm cleanup

src/drivers/samv7/tone_alarm/tone_alarm.cpp

@@ -388,13 +388,7 @@ void ToneAlarm::next_note()
 
 	if (updated) {
 		orb_copy(ORB_ID(tune_control), _tune_control_sub, &_tune);
-
-		if (_tunes.set_control(_tune) == 0) {
-			_play_tone = true;
-
-		} else {
-			_play_tone = false;
-		}
+		_play_tone = _tunes.set_control(_tune) == 0;
 	}
 
 	unsigned frequency = 0, duration = 0;