It may seem gratuitous, but it's what we really want. 

driverfs files are meant to expose attributes of various kernel objects, so in that sense,
the change adds more accurate meaning to the object.

Plus, we will soon gain the ability to expose attributes of drivers (both device and bus) 
themselves, and we want to be able to have each mean something reasonable.

This changes driverfs and the device model core (but none of the other users)