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/acl.c b/fs/btrfs/acl.c
index 6ef7b26..8d432cd 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -282,14 +282,14 @@
 	return ret;
 }
 
-struct xattr_handler btrfs_xattr_acl_default_handler = {
+const struct xattr_handler btrfs_xattr_acl_default_handler = {
 	.prefix = POSIX_ACL_XATTR_DEFAULT,
 	.flags	= ACL_TYPE_DEFAULT,
 	.get	= btrfs_xattr_acl_get,
 	.set	= btrfs_xattr_acl_set,
 };
 
-struct xattr_handler btrfs_xattr_acl_access_handler = {
+const struct xattr_handler btrfs_xattr_acl_access_handler = {
 	.prefix = POSIX_ACL_XATTR_ACCESS,
 	.flags	= ACL_TYPE_ACCESS,
 	.get	= btrfs_xattr_acl_get,