Control device activation from of_core instead of topology

[Ktmi]

Currently device activation/deactivation is handled by topology. This seems rather counter intuitive, as of_core is the NApp which generates the events which create the devices, and creates the events which then modify the activation state. This seems like an unnecessary level of indirection to have topology manage the activation/deactivation, when of_core already has already acquired the device for creating the event.