Remove comment about performance in qquickitem's clip property.
Remove comment about performance in qquickitem's clip property.

Change-Id: I2d1b9a86251466445d506969d779308e2d7b92bb
Reviewed-by: Samuel Rødal <99126055f8d73e4355b075213322026fa8c060bd@digia.com>

corngood/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,jfaust/qtdeclarative,mgrunditz/qtdeclarative-2d,jfaust/qtdeclarative,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,jfaust/qtdeclarative,corngood/qtdeclarative,jfaust/qtdeclarative,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,corngood/qtdeclarative,jfaust/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,jfaust/qtdeclarative,qmlc/qtdeclarative,corngood/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,corngood/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,matthewvogt/qtdeclarative,corngood/qtdeclarative,jfaust/qtdeclarative,qmlc/qtdeclarative,corngood/qtdeclarative