xfrm: Access the replay notify functions via the registered callbacks

We call the wrong replay notify function when we use ESN replay
handling. This leads to the fact that we don't send notifications
if we use ESN. Fix this by calling the registered callbacks instead
of xfrm_replay_notify().

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>