r8169: consider that 32 Bit DMA is the default

Documentation/DMA-API-HOWTO.txt states:
By default, the kernel assumes that your device can address 32-bits of
DMA addressing. For a 64-bit capable device, this needs to be increased,
and for a device with limitations, it needs to be decreased.

Therefore we don't need the 32 Bit DMA fallback configuration and can
remove it.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169_main.c

@@ -6724,15 +6724,8 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	tp->cp_cmd = RTL_R16(tp, CPlusCmd);
 
 	if (sizeof(dma_addr_t) > 4 && tp->mac_version >= RTL_GIGA_MAC_VER_18 &&
-	    !dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64))) {
+	    !dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)))
 		dev->features |= NETIF_F_HIGHDMA;
-	} else {
-		rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
-		if (rc < 0) {
-			dev_err(&pdev->dev, "DMA configuration failed\n");
-			return rc;
-		}
-	}
 
 	rtl_init_rxcfg(tp);