WavFile example: drop needless includes

Change-Id: I26033a3d853dca8023fe4ec5f1eb7c53ef5d013f
Reviewed-by: VaL Doroshchuk <valentyn.doroshchuk@qt.io>

examples/multimedia/spectrum/app/wavfile.cpp

@@ -49,9 +49,6 @@
 ****************************************************************************/
 
 #include <qendian.h>
-#include <QVector>
-#include <QDebug>
-#include "utils.h"
 #include "wavfile.h"
 
 struct chunk