quota: constify qtree_fmt_operations structures

The qtree_fmt_operations structures are never modified, so declare them as
const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/quota/quota_v2.c b/fs/quota/quota_v2.c
index 2aa012a..ed85d4f 100644
--- a/fs/quota/quota_v2.c
+++ b/fs/quota/quota_v2.c
@@ -30,13 +30,13 @@
 static void v2r1_disk2memdqb(struct dquot *dquot, void *dp);
 static int v2r1_is_id(void *dp, struct dquot *dquot);
 
-static struct qtree_fmt_operations v2r0_qtree_ops = {
+static const struct qtree_fmt_operations v2r0_qtree_ops = {
 	.mem2disk_dqblk = v2r0_mem2diskdqb,
 	.disk2mem_dqblk = v2r0_disk2memdqb,
 	.is_id = v2r0_is_id,
 };
 
-static struct qtree_fmt_operations v2r1_qtree_ops = {
+static const struct qtree_fmt_operations v2r1_qtree_ops = {
 	.mem2disk_dqblk = v2r1_mem2diskdqb,
 	.disk2mem_dqblk = v2r1_disk2memdqb,
 	.is_id = v2r1_is_id,