Makefile.proof: Add all source files to the dependencies

Change-Id: Ic1d19e4516bb20b9796ac02baee099e9df472ab5
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/17021
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
1 file changed