sb/intel/common: Declare common smbus_base() and enable_smbus()

This avoids including platform-specific headers with different
filenames from common code.

Change-Id: Idf9893e55949d63f3ceca2249e618d0f81320321
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38232
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/southbridge/intel/ibexpeak/early_smbus.c b/src/southbridge/intel/ibexpeak/early_smbus.c
index fdf0c32..52d483d 100644
--- a/src/southbridge/intel/ibexpeak/early_smbus.c
+++ b/src/southbridge/intel/ibexpeak/early_smbus.c
@@ -15,26 +15,27 @@
  */
 
 #include <device/pci_ops.h>
-#include <console/console.h>
 #include <device/pci_def.h>
 #include <device/smbus_host.h>
 #include "pch.h"
 
-void enable_smbus(void)
+uintptr_t smbus_base(void)
 {
-	pci_devfn_t dev;
+	return SMBUS_IO_BASE;
+}
 
+int smbus_enable_iobar(uintptr_t base)
+{
 	/* Set the SMBus device statically. */
-	dev = PCI_DEV(0x0, 0x1f, 0x3);
+	pci_devfn_t dev = PCI_DEV(0x0, 0x1f, 0x3);
 
 	/* Check to make sure we've got the right device. */
-	if (pci_read_config16(dev, 0x0) != 0x8086) {
-		die("SMBus controller not found!");
-	}
+	if (pci_read_config16(dev, 0x0) != 0x8086)
+		return -1;
 
 	/* Set SMBus I/O base. */
 	pci_write_config32(dev, SMB_BASE,
-			   SMBUS_IO_BASE | PCI_BASE_ADDRESS_SPACE_IO);
+			   base | PCI_BASE_ADDRESS_SPACE_IO);
 
 	/* Set SMBus enable. */
 	pci_write_config8(dev, HOSTC, HST_EN);
@@ -42,9 +43,7 @@
 	/* Set SMBus I/O space enable. */
 	pci_write_config16(dev, PCI_COMMAND, PCI_COMMAND_IO);
 
-	smbus_host_reset(SMBUS_IO_BASE);
-
-	printk(BIOS_DEBUG, "SMBus controller enabled.\n");
+	return 0;
 }
 
 int smbus_read_byte(unsigned int device, unsigned int address)