nb/i945/raminit.c: Use Makefile.inc instead of '#include rcven.c'

Change-Id: Ib86600b687c7002646ca82d5fa52121b6eafcd60
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/18087
Tested-by: build bot (Jenkins)
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
3 files changed