x86: i2c: Add a stub driver for Intel I2C/SMbus

This is used on most Intel platforms. We don't have a driver for it yet, but
add a stub to handle the init. For now this targets ivybridge so we may want
to add a device tree binding and generalise it when other platforms are
supported.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 14adda2..46b83e7 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -58,6 +58,15 @@
 	  bindings are supported.
 	  Binding info: doc/device-tree-bindings/i2c/i2c-gpio.txt
 
+config SYS_I2C_INTEL
+	bool "Intel I2C/SMBUS driver"
+	depends on DM_I2C
+	help
+	  Add support for the Intel SMBUS driver. So far this driver is just
+	  a stub which perhaps some basic init. There is no implementation of
+	  the I2C API meaning that any I2C operations will immediately fail
+	  for now.
+
 config SYS_I2C_ROCKCHIP
 	bool "Rockchip I2C driver"
 	depends on DM_I2C