drm/gma500: use container_of to resolve psb_fbdev from drm_fb_helper
drm/gma500: use container_of to resolve psb_fbdev from drm_fb_helper

Use container_of instead of casting first structure member.

Signed-off-by: Fabian Frederick <3efd2a027b14fd890cd23a9ef6d1134b4e5ad850@skynet.be>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs