QtMultimedia: micro-optimisation
QtMultimedia: micro-optimisation

Take Q_FOREACH's first argument by const-reference.
Avoids a copy.

Change-Id: I93c97d5de6b2ceecee4d1913d08d599d91aaf933
Reviewed-by: Thomas McGuire <2a8c2e178f359344f9cfed0db24d661e86eba971@kdab.com>

enthought/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,enthought/qt-mobility,enthought/qt-mobility,enthought/qt-mobility,enthought/qt-mobility,enthought/qt-mobility