libpayload: Add pci_free_dev() and some boilerplate

Add just enough code and boilerplate to keep it compatible with future
libflashrom.

Change-Id: If0d46fab141da525f8f115d3f6045a8c417569eb
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/20955
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2 files changed