src/superio/smsc/lpc47m15x: Avoid #include early_serial.c

Provide proper header and function type-signatures for Super I/O
romstage component.

Fix mainboard's bogous romstage component to match.

Change-Id: Icd02199690d0c428b2daadf702d50714dc367692
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5924
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
4 files changed