i2c: Let framebuffer drivers set their I2C bus class to DDC

Let framebuffer drivers set their I2C bus class to DDC. Once this is
done, we will be able to tell the eeprom driver to only probe for
EDID EEPROMs on these buses.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 7c36d51..145797f 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -349,7 +349,7 @@
 #define I2C_CLASS_HWMON		(1<<0)	/* lm_sensors, ... */
 #define I2C_CLASS_TV_ANALOG	(1<<1)	/* bttv + friends */
 #define I2C_CLASS_TV_DIGITAL	(1<<2)	/* dvb cards */
-#define I2C_CLASS_DDC		(1<<3)	/* i2c-matroxfb ? */
+#define I2C_CLASS_DDC		(1<<3)	/* DDC bus on graphics adapters */
 #define I2C_CLASS_CAM_ANALOG	(1<<4)	/* camera with analog CCD */
 #define I2C_CLASS_CAM_DIGITAL	(1<<5)	/* most webcams */
 #define I2C_CLASS_SOUND		(1<<6)	/* sound devices */