libertas: remove double assignment of dev->netdev_ops

This came in through the patch titled:
    libertas: first stab at cfg80211 support

I only noticed it because it breaks compat-wireless :)
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Acked-by: Holger Schurig <hs4233@mail.mn-solutions.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/libertas/main.c

@@ -1276,7 +1276,6 @@ struct lbs_private *lbs_add_card(void *card, struct device *dmdev)
 		goto err_adapter;
 	}
 
-	dev->netdev_ops = &lbs_netdev_ops;
 	dev->ieee80211_ptr = wdev;
 	dev->ml_priv = priv;
 	SET_NETDEV_DEV(dev, dmdev);