r8169: improve rtl8169_irq_mask_and_ack

Code can be slightly simplified by acking even events we're not
interested in. In addition add a comment making clear that the
read has no functional purpose and is just a PCI commit.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169.c

@@ -1352,7 +1352,8 @@ static void rtl_irq_enable_all(struct rtl8169_private *tp)
 static void rtl8169_irq_mask_and_ack(struct rtl8169_private *tp)
 {
 	rtl_irq_disable(tp);
-	rtl_ack_events(tp, RTL_EVENT_NAPI | tp->event_slow);
+	rtl_ack_events(tp, 0xffff);
+	/* PCI commit */
 	RTL_R8(tp, ChipCmd);
 }
 
@@ -7365,14 +7366,12 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	rtl_init_rxcfg(tp);
 
-	rtl_irq_disable(tp);
+	rtl8169_irq_mask_and_ack(tp);
 
 	rtl_hw_initialize(tp);
 
 	rtl_hw_reset(tp);
 
-	rtl_ack_events(tp, 0xffff);
-
 	pci_set_master(pdev);
 
 	rtl_init_mdio_ops(tp);