r8169: remove hardcoded PCIe registers accesses.

Signed-off-by: NFrancois Romieu <romieu@fr.zoreil.com>

drivers/net/ethernet/realtek/r8169.c

@@ -3824,23 +3824,21 @@ static void r8168dp_hw_jumbo_disable(struct rtl8169_private *tp)
 static void r8168e_hw_jumbo_enable(struct rtl8169_private *tp)
 {
 	void __iomem *ioaddr = tp->mmio_addr;
-	struct pci_dev *pdev = tp->pci_dev;
 
 	RTL_W8(MaxTxPacketSize, 0x3f);
 	RTL_W8(Config3, RTL_R8(Config3) | Jumbo_En0);
 	RTL_W8(Config4, RTL_R8(Config4) | 0x01);
-	pci_write_config_byte(pdev, 0x79, 0x20);
+	rtl_tx_performance_tweak(tp->pci_dev, 0x2 << MAX_READ_REQUEST_SHIFT);
 }
 
 static void r8168e_hw_jumbo_disable(struct rtl8169_private *tp)
 {
 	void __iomem *ioaddr = tp->mmio_addr;
-	struct pci_dev *pdev = tp->pci_dev;
 
 	RTL_W8(MaxTxPacketSize, 0x0c);
 	RTL_W8(Config3, RTL_R8(Config3) & ~Jumbo_En0);
 	RTL_W8(Config4, RTL_R8(Config4) & ~0x01);
-	pci_write_config_byte(pdev, 0x79, 0x50);
+	rtl_tx_performance_tweak(tp->pci_dev, 0x5 << MAX_READ_REQUEST_SHIFT);
 }
 
 static void r8168b_0_hw_jumbo_enable(struct rtl8169_private *tp)