QCanbusDevice::Filter lacks the support of the == operator

When I use the method `QVariant QCanBusDevice::configurationParameter(int key)` to get a `QList<QCanBusDevice::Filter>` via `QCanBusDevice::RawFilterKey`, I noticed, that I cannot compare the QVariant returned with a different `QVariant::fromValue(QList<QCanBusDevice::Filter>)`. This is due to the fact that the `QCanBusDevice::Filter` does not implement the == operator for comparison.

 Could that get added?