btrfs: constify xattr_handler

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 193b58f..59acd3e 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -282,7 +282,7 @@
  * List of handlers for synthetic system.* attributes.  All real ondisk
  * attributes are handled directly.
  */
-struct xattr_handler *btrfs_xattr_handlers[] = {
+const struct xattr_handler *btrfs_xattr_handlers[] = {
 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
 	&btrfs_xattr_acl_access_handler,
 	&btrfs_xattr_acl_default_handler,