Smatch complains that the "add_bytes" is not to be trusted. Use
size_add() to prevent an integer overflow.
Fixes: be71b5cba2 ("fs/ntfs3: Add attrib operations")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>