r8169: never set PCI_EXP_DEVCTL_NOSNOOP_EN

Setting PCI_EXP_DEVCTL_NOSNOOP_EN for certain chip versions had been
added to the vendor driver more than 10 years ago, and copied from
there to r8169. It has been removed from the vendor driver meanwhile
and I think we can safely remove this too.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169_main.c

@@ -5345,19 +5345,6 @@ static void rtl_hw_start_8125(struct rtl8169_private *tp)
 
 static void rtl_hw_start_8168(struct rtl8169_private *tp)
 {
-	switch (tp->mac_version) {
-	case RTL_GIGA_MAC_VER_11:
-	case RTL_GIGA_MAC_VER_12:
-	case RTL_GIGA_MAC_VER_13:
-	case RTL_GIGA_MAC_VER_16:
-	case RTL_GIGA_MAC_VER_17:
-		pcie_capability_set_word(tp->pci_dev, PCI_EXP_DEVCTL,
-					 PCI_EXP_DEVCTL_NOSNOOP_EN);
-		break;
-	default:
-		break;
-	}
-
 	if (rtl_is_8168evl_up(tp))
 		RTL_W8(tp, MaxTxPacketSize, EarlySize);
 	else