net_sched: move dev_graft_qdisc() to sch_generic.c

It will be used in a following patch by the multiqueue qdisc.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index a48a4cc..a92dc62 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -302,6 +302,8 @@
 extern void dev_shutdown(struct net_device *dev);
 extern void dev_activate(struct net_device *dev);
 extern void dev_deactivate(struct net_device *dev);
+extern struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
+				     struct Qdisc *qdisc);
 extern void qdisc_reset(struct Qdisc *qdisc);
 extern void qdisc_destroy(struct Qdisc *qdisc);
 extern void qdisc_tree_decrease_qlen(struct Qdisc *qdisc, unsigned int n);