net: sched: sch: add extack to change class

This patch adds extack support for class change callback api. This prepares
to handle extack support inside each specific class implementation.

Cc: David Ahern <dsahern@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index fcc7041..6cf2f7d 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1907,7 +1907,7 @@
 	new_cl = cl;
 	err = -EOPNOTSUPP;
 	if (cops->change)
-		err = cops->change(q, clid, portid, tca, &new_cl);
+		err = cops->change(q, clid, portid, tca, &new_cl, extack);
 	if (err == 0) {
 		tclass_notify(net, skb, n, q, new_cl, RTM_NEWTCLASS);
 		/* We just create a new class, need to do reverse binding. */