sctp: fix return value check in __sctp_rcv_asconf_lookup

As Ben Hutchings noticed, this check should have been inverted: the call
returns true in case of success.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Fixes: 0c5dc070ff3d ("sctp: validate from_addr_param return")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/input.c b/net/sctp/input.c
index eb3c2a3..5ef86fd 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -1203,7 +1203,7 @@
 	if (unlikely(!af))
 		return NULL;
 
-	if (af->from_addr_param(&paddr, param, peer_port, 0))
+	if (!af->from_addr_param(&paddr, param, peer_port, 0))
 		return NULL;
 
 	return __sctp_lookup_association(net, laddr, &paddr, transportp);