const: mark remaining address_space_operations 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/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 156bf60..680e86c 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -427,7 +427,7 @@
 }
 
 
-static struct address_space_operations def_mdt_aops = {
+static const struct address_space_operations def_mdt_aops = {
 	.writepage		= nilfs_mdt_write_page,
 	.sync_page		= block_sync_page,
 };