net/ieee80211: adjust error handling

Converts a test in error handling code to a sequence of labels.

The semantic match that found the problem is:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression E,E1,E2;
@@

E = alloc_etherdev(...)
... when != E = E1
if (...) { ... free_netdev(E); ... return ...; }
... when != E = E2
(
  if (...)
   {
   ... when != free_netdev(E);
   return dev; }
|
* if (...)
   {
   ... when != free_netdev(E);
   return ...; }
|
register_netdev(E)
)

// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

net/ieee80211/ieee80211_module.c

@@ -157,7 +157,7 @@ struct net_device *alloc_ieee80211(int sizeof_priv)
 	err = ieee80211_networks_allocate(ieee);
 	if (err) {
 		IEEE80211_ERROR("Unable to allocate beacon storage: %d\n", err);
-		goto failed;
+		goto failed_free_netdev;
 	}
 	ieee80211_networks_initialize(ieee);
 
@@ -193,9 +193,9 @@ struct net_device *alloc_ieee80211(int sizeof_priv)
 
 	return dev;
 
-      failed:
-	if (dev)
-		free_netdev(dev);
+failed_free_netdev:
+	free_netdev(dev);
+failed:
 	return NULL;
 }