drivers/video/bf54x-lq043fb.c: use devm_ functions

The various devm_ functions allocate memory that is released when a driver
detaches. This patch replaces the use of kzalloc by devm_kzalloc.

Signed-off-by: Damien Cassou <damien.cassou@lifl.fr>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>