sctp: fix integer overflow when setting the autoclose timer

When setting the autoclose timeout in jiffies there is a possible
integer overflow if the value in seconds is very large
(e.g. for 2^22 s with HZ=1024). The problem appears even on
64-bit due to the integer promotion rules. The fix is just a cast
 to unsigned long.
Signed-off-by: Andrei Pelinescu-Onciul <andrei@iptel.org>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

net/sctp/associola.c

@@ -167,7 +167,7 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
 	asoc->timeouts[SCTP_EVENT_TIMEOUT_HEARTBEAT] = 0;
 	asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay;
 	asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
-		sp->autoclose * HZ;
+		(unsigned long)sp->autoclose * HZ;
 
 	/* Initilizes the timers */
 	for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i)