drm: Pass the user drm_mode_fb_cmd2 as const to .fb_create()

Drivers shouldn't clobber the passed in addfb ioctl parameters.
i915 was doing just that. To prevent it from happening again,
pass the struct around as const, starting all the way from
internal_framebuffer_create().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.h b/drivers/gpu/drm/mgag200/mgag200_drv.h
index 912151c..205b280 100644
--- a/drivers/gpu/drm/mgag200/mgag200_drv.h
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.h
@@ -252,7 +252,7 @@
 				/* mgag200_main.c */
 int mgag200_framebuffer_init(struct drm_device *dev,
 			     struct mga_framebuffer *mfb,
-			     struct drm_mode_fb_cmd2 *mode_cmd,
+			     const struct drm_mode_fb_cmd2 *mode_cmd,
 			     struct drm_gem_object *obj);