nl80211: fix a station dump crash triggered by sending an invalid ifindex

SVN-Revision: 23741

package/mac80211/patches/300-nl80211_dump_crash_fix.patch

+--- a/net/wireless/nl80211.c
++++ b/net/wireless/nl80211.c
+@@ -224,8 +224,8 @@ static int nl80211_prepare_netdev_dump(s
+ 	}
+ 
+ 	*rdev = cfg80211_get_dev_from_ifindex(sock_net(skb->sk), ifidx);
+-	if (IS_ERR(dev)) {
+-		err = PTR_ERR(dev);
++	if (IS_ERR(*rdev)) {
++		err = PTR_ERR(*rdev);
+ 		goto out_rtnl;
+ 	}
+