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/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index f47cefa..173535a 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -996,7 +996,7 @@
 struct drm_mode_config_funcs {
 	struct drm_framebuffer *(*fb_create)(struct drm_device *dev,
 					     struct drm_file *file_priv,
-					     struct drm_mode_fb_cmd2 *mode_cmd);
+					     const struct drm_mode_fb_cmd2 *mode_cmd);
 	void (*output_poll_changed)(struct drm_device *dev);
 
 	int (*atomic_check)(struct drm_device *dev,