drivers/video/udlfb bind framebuffer to interface.

Udlfb has been binding the framebuffer device to its parent, which
isn't correct and causes confusion with operations like udev remove.

Coming plug and play multiseat support is dependent on this fix.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>