drivers/video/au*fb.c: use devm_ functions

The various devm_ functions allocate memory that is released when a driver
detaches.  This patch uses these functions for data that is allocated in
the probe function of a platform device and is only freed in the remove
function.

In au1100fb.c, the probe function now returns -ENODEV on failure.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Manuel Lauss <manuel.lauss@googlemail.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>