roda/rk9: Remove #include early_serial.c from romstage

Remove dependency on early_serial.c and instead use the
Super I/O's header to access the functions needed.
Also re-organize some of the superio code in order
to succesfully compile the rom.

Change-Id: I85a6f1352ae3b91c3c98e4d3fa0b90b87e02babc
Signed-off-by: Antonello Dettori <dev@dettori.io>
Reviewed-on: https://review.coreboot.org/13925
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
5 files changed