forcedeth: spin_unlock_irq in interrupt handler fix

The replacement of spin_lock_irq/spin_unlock_irq pair in interrupt
handler by spin_lock_irqsave/spin_lock_irqrestore pair.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NDenis Efremov <yefremov.denis@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/nvidia/forcedeth.c

@@ -3775,7 +3775,7 @@ static irqreturn_t nv_nic_irq_other(int foo, void *data)
 			np->link_timeout = jiffies + LINK_TIMEOUT;
 		}
 		if (events & NVREG_IRQ_RECOVER_ERROR) {
-			spin_lock_irq(&np->lock);
+			spin_lock_irqsave(&np->lock, flags);
 			/* disable interrupts on the nic */
 			writel(NVREG_IRQ_OTHER, base + NvRegIrqMask);
 			pci_push(base);
@@ -3785,7 +3785,7 @@ static irqreturn_t nv_nic_irq_other(int foo, void *data)
 				np->recover_error = 1;
 				mod_timer(&np->nic_poll, jiffies + POLL_WAIT);
 			}
-			spin_unlock_irq(&np->lock);
+			spin_unlock_irqrestore(&np->lock, flags);
 			break;
 		}
 		if (unlikely(i > max_interrupt_work)) {