r8169: balance pci_map / pci_unmap pair

The leak hurts with swiotlb and jumbo frames.

Fix http://bugzilla.kernel.org/show_bug.cgi?id=9468.

Heavily hinted by Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>.
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Tested-by: Alistair John Strachan <alistair@devzero.co.uk>
Tested-by: Timothy J Fontaine <tjfontaine@atxconsulting.com>
Cc: Edward Hsu <edward_hsu@realtek.com.tw>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/r8169.c

@@ -2792,7 +2792,7 @@ static int rtl8169_rx_interrupt(struct net_device *dev,
 					pkt_size, PCI_DMA_FROMDEVICE);
 				rtl8169_mark_to_asic(desc, tp->rx_buf_sz);
 			} else {
-				pci_unmap_single(pdev, addr, pkt_size,
+				pci_unmap_single(pdev, addr, tp->rx_buf_sz,
 						 PCI_DMA_FROMDEVICE);
 				tp->Rx_skbuff[entry] = NULL;
 			}