sb/intel/*: Use common SMBus functions

All Intel southbridges implement the same SMBus functions.
This patch replaces all these similar and mostly identical
implementations with a common file.

This also makes i2c block read available to all those southbridges.
If the northbridge has to read a lot of SPD bytes sequentially, using
this function can reduce the time being spent to read SPD five-fold.

Change-Id: I93bb186e04e8c32dff04fc1abe4b5ecbc4c9c962
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/19258
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/southbridge/intel/ibexpeak/early_smbus.c

@@ -18,8 +18,8 @@
 #include <console/console.h>
 #include <device/pci_ids.h>
 #include <device/pci_def.h>
+#include <southbridge/intel/common/smbus.h>
 #include "pch.h"
-#include "smbus.h"
 
 void enable_smbus(void)
 {