[PATCH] radeonfb: prevent spurious recompilations

Prevent spurious recompilations of the radeonfb driver when I2C/DDC support
is not included and i2c header files are modified.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>