soc/intel/common/block/smbus: Add define for I2C_EN

Change-Id: Iecccc363f492985555019f2390bd53472a000ba9
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46563
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/intel/common/block/smbus/smbuslib.h

@@ -9,6 +9,8 @@
 /* PCI Configuration Space : SMBus */
 #define HOSTC	0x40
 #define HST_EN	(1 << 0)
+#define I2C_EN  (1 << 2)
+
 /* SMBus I/O bits. */
 #define SMBHSTSTAT	0x0
 #define SMBHSTCTL	0x2