qdev_class_add_property() and qdev_property_add_static() will
have code that's specific for device types.
object_class_property_add_static(),
object_class_add_static_props(), and object_property_add_static()
will be generic and part of the QOM static property API.
The declarations for the new functions are being added to
qdev-properties.h, but they will be moved to a QOM header later.
Might be worth to mention that you also changed *property_add_static() to return the ObjectProperty. Probably useful in a later patch.