constify dentry_operations: GFS2

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/gfs2/super.h b/fs/gfs2/super.h
index f6b8b00..a931e44 100644
--- a/fs/gfs2/super.h
+++ b/fs/gfs2/super.h
@@ -47,7 +47,7 @@
 extern struct file_system_type gfs2meta_fs_type;
 extern const struct export_operations gfs2_export_ops;
 extern const struct super_operations gfs2_super_ops;
-extern struct dentry_operations gfs2_dops;
+extern const struct dentry_operations gfs2_dops;
 
 #endif /* __SUPER_DOT_H__ */