sctp: Make the ctl_sock per network namespace

- Kill sctp_get_ctl_sock, it is useless now.
- Pass struct net where needed so net->sctp.ctl_sock is accessible.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/input.c b/net/sctp/input.c
index a7e9a85..c9a0449 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -204,7 +204,7 @@
 			sctp_endpoint_put(ep);
 			ep = NULL;
 		}
-		sk = sctp_get_ctl_sock();
+		sk = net->sctp.ctl_sock;
 		ep = sctp_sk(sk)->ep;
 		sctp_endpoint_hold(ep);
 		rcvr = &ep->base;
@@ -795,7 +795,7 @@
 			goto hit;
 	}
 
-	ep = sctp_sk((sctp_get_ctl_sock()))->ep;
+	ep = sctp_sk(net->sctp.ctl_sock)->ep;
 
 hit:
 	sctp_endpoint_hold(ep);