fbdev: fix au1*fb builds

Commit 1c16697b
("drivers/video/au*fb.c: use devm_ functions) introduced 2 build failures
in the au1100fb and au1200fb drivers, fix them.

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