superio/smsc/smscsuperio: Make romstage linkable with header

Rewrite smsc/smscsuperio romstage component to be more consistent and
provide header there-by removing #include's of early_serial.c's in
mainboard's.

Change-Id: I572e0c76422f09d4de88935a36c0a59e5350e6e0
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5915
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
15 files changed