Reduce number of per-mainboard changes

- Add mainboard_smi.c from arch/x86/Makefile if it's there
- Add mainboard's chromeos.c from the chromeos Makefile

Change-Id: I3f80e2cb368f88d2a38036895a19f3576dd9553b
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/1835
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
15 files changed