[TG3]: Add missing unlock in tg3_open() error path.

Sparse noticed a locking imbalance in tg3_open(). This patch adds an
unlock to one of the error paths, so that tg3_open() always exits
without the lock held.
Signed-off-by: NIra W. Snyder <kernel@irasnyder.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -6979,8 +6979,10 @@ static int tg3_open(struct net_device *dev)
 	tg3_full_lock(tp, 0);
 
 	err = tg3_set_power_state(tp, PCI_D0);
-	if (err)
+	if (err) {
+		tg3_full_unlock(tp);
 		return err;
+	}
 
 	tg3_disable_ints(tp);
 	tp->tg3_flags &= ~TG3_FLAG_INIT_COMPLETE;