sb/intel: Define CONFIG_FIXED_SMBUS_IO_BASE

Make it default to 0x400, which is what the touched southbridges use.

Change-Id: I95cb1730d5bf6f596ed1ca8e7dba40b6a9e882fe
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43037
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/northbridge/intel/haswell/romstage.c b/src/northbridge/intel/haswell/romstage.c
index 39babf5..5b025eb 100644
--- a/src/northbridge/intel/haswell/romstage.c
+++ b/src/northbridge/intel/haswell/romstage.c
@@ -51,7 +51,7 @@
 		.dmibar			= (uintptr_t)DEFAULT_DMIBAR,
 		.epbar			= DEFAULT_EPBAR,
 		.pciexbar		= CONFIG_MMCONF_BASE_ADDRESS,
-		.smbusbar		= SMBUS_IO_BASE,
+		.smbusbar		= CONFIG_FIXED_SMBUS_IO_BASE,
 		.hpet_address		= HPET_ADDR,
 		.rcba			= (uintptr_t)DEFAULT_RCBA,
 		.pmbase			= DEFAULT_PMBASE,