net: sched: rename qdisc_destroy() to qdisc_put()

Current implementation of qdisc_destroy() decrements Qdisc reference
counter and only actually destroy Qdisc if reference counter value reached
zero. Rename qdisc_destroy() to qdisc_put() in order for it to better
describe the way in which this function currently implemented and used.

Extract code that deallocates Qdisc into new private qdisc_destroy()
function. It is intended to be shared between regular qdisc_put() and its
unlocked version that is introduced in next patch in this series.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.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 411c403..2096138 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -920,7 +920,7 @@
 		qdisc_notify(net, skb, n, clid, old, new);
 
 	if (old)
-		qdisc_destroy(old);
+		qdisc_put(old);
 }
 
 /* Graft qdisc "new" to class "classid" of qdisc "parent" or
@@ -973,7 +973,7 @@
 				qdisc_refcount_inc(new);
 
 			if (!ingress)
-				qdisc_destroy(old);
+				qdisc_put(old);
 		}
 
 skip:
@@ -1561,7 +1561,7 @@
 	err = qdisc_graft(dev, p, skb, n, clid, q, NULL, extack);
 	if (err) {
 		if (q)
-			qdisc_destroy(q);
+			qdisc_put(q);
 		return err;
 	}