[NET]: Add some acquires/releases sparse annotations.

Add __acquires() and __releases() annotations to suppress some sparse
warnings.

example of warnings :

net/ipv4/udp.c:1555:14: warning: context imbalance in 'udp_seq_start' - wrong
count at exit
net/ipv4/udp.c:1571:13: warning: context imbalance in 'udp_seq_stop' -
unexpected unlock

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 9be2f15..ea5a05b 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -40,12 +40,16 @@
  */
 
 void qdisc_lock_tree(struct net_device *dev)
+	__acquires(dev->queue_lock)
+	__acquires(dev->ingress_lock)
 {
 	spin_lock_bh(&dev->queue_lock);
 	spin_lock(&dev->ingress_lock);
 }
 
 void qdisc_unlock_tree(struct net_device *dev)
+	__releases(dev->ingress_lock)
+	__releases(dev->queue_lock)
 {
 	spin_unlock(&dev->ingress_lock);
 	spin_unlock_bh(&dev->queue_lock);