Move C source code in its subdirectory

Change-Id: I98611e8c3c7cdb6aa68c99c0cee83d868283d0af
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@no-log.org>
Reviewed-on: https://review.coreboot.org/18531
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
15 files changed