net: davicom: Use platform_get_irq_optional()

The second IRQ line really is optional, so use
platform_get_irq_optional() to obtain it.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/davicom/dm9000.c

@@ -1507,7 +1507,7 @@ dm9000_probe(struct platform_device *pdev)
 		goto out;
 	}
 
-	db->irq_wake = platform_get_irq(pdev, 1);
+	db->irq_wake = platform_get_irq_optional(pdev, 1);
 	if (db->irq_wake >= 0) {
 		dev_dbg(db->dev, "wakeup irq %d\n", db->irq_wake);