aoe: remove dev_base_lock use from aoecmd_cfg_pkts()

dev_base_lock is the legacy way to lock the device list, and is planned
to disappear. (writers hold RTNL, readers hold RCU lock)

Convert aoecmd_cfg_pkts() to RCU locking.

Signed-off-by: Eric Dumazet <[e-mail]>
Cc: "Ed L. Cashin" <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/block/aoe/aoecmd.c

···
 	struct sk_buff *skb;
 	struct net_device *ifp;
 
-	read_lock(&dev_base_lock);
-	for_each_netdev(&init_net, ifp) {
+	rcu_read_lock();
+	for_each_netdev_rcu(&init_net, ifp) {
 		dev_hold(ifp);
 		if (!is_aoe_netif(ifp))
 			goto cont;
···
 cont:
 		dev_put(ifp);
 	}
-	read_unlock(&dev_base_lock);
+	rcu_read_unlock();
 }
 
 static void