drm: Constify struct drm_info_list * arguments

Those functions are just reading data from those pointers.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

include/drm/drmP.h

@@ -1477,10 +1477,11 @@ extern struct drm_local_map *drm_getsarea(struct drm_device *dev);
 #if defined(CONFIG_DEBUG_FS)
 extern int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 			    struct dentry *root);
-extern int drm_debugfs_create_files(struct drm_info_list *files, int count,
-				    struct dentry *root, struct drm_minor *minor);
-extern int drm_debugfs_remove_files(struct drm_info_list *files, int count,
-                                    struct drm_minor *minor);
+extern int drm_debugfs_create_files(const struct drm_info_list *files,
+				    int count, struct dentry *root,
+				    struct drm_minor *minor);
+extern int drm_debugfs_remove_files(const struct drm_info_list *files,
+				    int count, struct drm_minor *minor);
 extern int drm_debugfs_cleanup(struct drm_minor *minor);
 #endif