tg3: Fix inconsistent locking for tg3_netif_start().

Every caller holds tp->lock when calling tg3_netif_start() except
tg3_io_resume().  Fix it so that it is all consistent.  The subsequent
PTP patches add tg3_ptp_resume() to tg3_netif_start() and the tp->lock
is required.

Signed-off-by: Nithin Nayak Sujir <nsujir@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.c

@@ -6525,6 +6525,7 @@ static inline void tg3_netif_stop(struct tg3 *tp)
 	netif_tx_disable(tp->dev);
 }
 
+/* tp->lock must be held */
 static inline void tg3_netif_start(struct tg3 *tp)
 {
 	/* NOTE: unconditional netif_tx_wake_all_queues is only
@@ -16599,8 +16600,8 @@ static void tg3_io_resume(struct pci_dev *pdev)
 	tg3_full_lock(tp, 0);
 	tg3_flag_set(tp, INIT_COMPLETE);
 	err = tg3_restart_hw(tp, 1);
-	tg3_full_unlock(tp);
 	if (err) {
+		tg3_full_unlock(tp);
 		netdev_err(netdev, "Cannot restart hardware after reset.\n");
 		goto done;
 	}
@@ -16611,6 +16612,8 @@ static void tg3_io_resume(struct pci_dev *pdev)
 
 	tg3_netif_start(tp);
 
+	tg3_full_unlock(tp);
+
 	tg3_phy_start(tp);
 
 done: