cygnus' serial driver wasn't part of the tree when the big transformation was done, so follow up. Change-Id: Ic1a53bea9bcaf1e568b50b9c2ad7782e65e36328 Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Reviewed-on: http://review.coreboot.org/9852 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>