entity-manager frudevice interface

[Patrick Venture]

James;

As you know, I've started adding:

"xyz.openbmc_project.Inventory.Decorator.FruDevice": {
"Bus": "$bus",
"Address": "$address"
}

To my json files.  But I was wondering, this feature -- being able to
point back to a FruDevice by bus+addess may be sufficiently useful
that entity-manager always adds it when the probe result has a
bus+address.

Thoughts?

Patrick