fbdev: rework FB_DDC dependencies

Selecting FB_DDC currently turns on CONFIG_I2C implicitly,
which is often not desired and can lead to circular dependencies.

Change this to a 'depends on' and change all drivers that
rely on FB_DDC to have an appropriate I2C dependency as well.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
1 file changed