const: constify remaining file_operations

[akpm@linux-foundation.org: fix KVM]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nilfs2/mdt.c

@@ -433,7 +433,7 @@ static const struct address_space_operations def_mdt_aops = {
 };
 
 static const struct inode_operations def_mdt_iops;
-static struct file_operations def_mdt_fops;
+static const struct file_operations def_mdt_fops;
 
 /*
  * NILFS2 uses pseudo inodes for meta data files such as DAT, cpfile, sufile,