commit b19cbe2a [BRIDGE]: Fix fdb RCU
race

breaks sparc SMP build because atomic_add_unless is not exported.

This patch exports atomic_add_unless and atomic_cmpxchg.
Signed-off-by: NRobert Reif <reif@earthlink.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>