libpayload: Add enum for USB speeds

These values are already used in this usb stack.

Change-Id: If96f1dc2b67fbc13dfc4ae2d84e8f9945aa03163
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/3448
Reviewed-by: Anton Kochkov <anton.kochkov@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
1 file changed