[PATCH] USB: add support for AT91 gadget

This adds support for the USB peripheral controller on AT91
(rm9200, eventually also sam9261 or uClinux) platforms.

More SOC support for Linux-USB ... an uncomplicated pure PIO driver.
It'd be worth using this as a model, if you're starting a driver
for some other peripheral controller.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>