This adds support for usb interrupt transfers in the EHCI driver. Split
transactions are supported, so this enables support for HID keyboards
devices over hubs in high-speed mode.
Change-Id: I9eb08f12b12c67ece10814952cb8651278b02f9d
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/1083
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>