geniviextras: Fix potential crash during Qt cleanup V2

[kirmitrahovich]

Access to static object pointer by QGlobalStatic::operator->() never return a null pointer even if object was destroyed.

[kirmitrahovich]

Another possible solution might be to use implicit conversion in the globalDltRegistration:

QDltRegistration *globalDltRegistration()
{
    return dltRegistration;
}