intel SMI handlers: Refactor GPI SMI/SCI routing

Move the GPI interrupt routing selection between SMI/SCI from
mainboards to southbridge. There is speculation if this is all
just legacy APM stuff that could be removed with a followup.

Change-Id: Iab14cf347584513793f417febc47f0559e17f5a5
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Signed-off-by: Nicolas Reinecke <nr@das-labor.org>
Reviewed-on: http://review.coreboot.org/7967
Tested-by: build bot (Jenkins)
Reviewed-by: Alexander Couzens <lynxis@fe80.eu>
23 files changed