[U-Boot] USB and unbinding

[Simon Glass]

Hi Hans,

I've been thinking about the USB unbinding code. I know that I agreed
to go with it, but in retrospect I think that was a mistake.

I believe we should separate out the unbinding and make it an option,
so that it is not required in order to use USB. In effect this makes
one of driver model's design goals (the option to drop unused code)
useless since USB is a common interface.

If I recall the only problem the lack of unbinding caused was that the
keyboard driver broke. I suspect it broke in a way that can be fixed.
In fact I recently converted usb_ether to driver model and I'm willing
to do the keyboard side also.

I'd like the USB code to function with or without the unbinding (i.e.
it uses it if there). What do you think?

Regards,
Simon