r8169: improve spurious interrupt detection

Improve detection of spurious interrupts by checking against the
interrupt mask as currently set in the chip.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -6405,8 +6405,9 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
 {
 	struct rtl8169_private *tp = dev_instance;
 	u16 status = rtl_get_events(tp);
+	u16 irq_mask = RTL_R16(tp, IntrMask);
 
-	if (status == 0xffff || !(status & tp->irq_mask))
+	if (status == 0xffff || !(status & irq_mask))
 		return IRQ_NONE;
 
 	if (unlikely(status & SYSErr)) {