This fixes up a typo in the ll/sc based cmpxchg code which apparently
wasn't getting a lot of testing due to the swapped old/new pair. With
that fixed up, the ll/sc code also starts using it and provides its own
atomic_add_unless().
Signed-off-by: NAoi Shinkai <shinkoi2005@gmail.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>