drivers/video: compile fixes for fsl-diu-fb.c

Fix a compiler errors introduced in:
  commit ddd3d905
  Author: Timur Tabi <timur@freescale.com>
  drivers/video: fsl-diu-fb: merge all allocated data into one block

Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>