Fix typo in the function argument of QRect::moveTo: t -> y

Task-number: QTBUG-36259

Change-Id: If6f8da7f36d9a2bc171f2f50d36b37af8f13d8d0
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>