sctp: support sysctl to allow users to use stream interleave

This is the last patch for support of stream interleave, after this patch,
users could enable stream interleave by systcl -w net.sctp.intl_enable=1.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/sysctl.c

@@ -288,6 +288,13 @@ static struct ctl_table sctp_net_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_sctp_do_auth,
 	},
+	{
+		.procname	= "intl_enable",
+		.data		= &init_net.sctp.intl_enable,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
 	{
 		.procname	= "addr_scope_policy",
 		.data		= &init_net.sctp.scope_policy,