Is it true that for on-board devices, it can sometimes be legitimate
and useful to be able to deliver platform_data from the board file
through to stuff on a USB bus, same as you would for memory mapped,
I2C, other busses?
Or is that it since it is USB, it can never be useful or legitimate,
no matter what different kind of wired-up on-board USB device it is,
to have the board definition file configure the driver for that
instantiation?
Since it is USB, it is always discoverable, so it doesn't make any sense
to have this type of thing.
And since your only example was a network device, I think you proved
your point :)