const: make struct super_block::dq_op const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 90162fb..83e1a0c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1318,7 +1318,7 @@
 	unsigned long long	s_maxbytes;	/* Max file size */
 	struct file_system_type	*s_type;
 	const struct super_operations	*s_op;
-	struct dquot_operations	*dq_op;
+	const struct dquot_operations	*dq_op;
  	struct quotactl_ops	*s_qcop;
 	const struct export_operations *s_export_op;
 	unsigned long		s_flags;