drm: Constify drm_mode_config_funcs pointer

The DRM mode config functions structure declared by drivers and pointed
to by the drm_mode_config funcs field is never modified. Make it a const
pointer.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Rob Clark <rob.clark@linaro.org>
Reviwed-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index 09cd23c..5732b57 100644
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -782,7 +782,7 @@
 	dev->mode_config.min_width = 0;
 	dev->mode_config.min_height = 0;
 
-	dev->mode_config.funcs = (void *) &psb_mode_funcs;
+	dev->mode_config.funcs = &psb_mode_funcs;
 
 	/* set memory base */
 	/* Oaktrail and Poulsbo should use BAR 2*/