sctp: Add missing annotation for sctp_err_finish()

Sparse reports a warning at sctp_err_finish()
warning: context imbalance in sctp_err_finish() - unexpected unlock

The root cause is a missing annotation at sctp_err_finish()
Add the missing  __releases(&((__sk)->sk_lock.slock)) annotation
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/input.c

@@ -548,6 +548,7 @@ struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
 
 /* Common cleanup code for icmp/icmpv6 error handler. */
 void sctp_err_finish(struct sock *sk, struct sctp_transport *t)
+	__releases(&((__sk)->sk_lock.slock))
 {
 	bh_unlock_sock(sk);
 	sctp_transport_put(t);