[netdrvr pcnet32] add missing pci_dma_sync_single

a patch for the pcnet32.c driver which adds a missing call to
pci_dma_sync_single.  If a received packet is smaller than rx_copybreak
the pcnet driver will recycle the receive buffer which requires calling
pci_dma_sync_single.  Patch is against 2.6 but I it's also needed in 2.4.

Without that call the processor might still have old stale data in
the data cache when the processor accesses the recycled buffer.

drivers/net/pcnet32.c

@@ -1376,6 +1376,10 @@ pcnet32_rx(struct net_device *dev)
 		if (!rx_in_place) {
 		    skb_reserve(skb,2); /* 16 byte align */
 		    skb_put(skb,pkt_len);	/* Make room */
+		    pci_dma_sync_single(lp->pci_dev,
+		                        lp->rx_dma_addr[entry],
+		                        PKT_BUF_SZ,
+		                        PCI_DMA_FROMDEVICE);
 		    eth_copy_and_sum(skb,
 				     (unsigned char *)(lp->rx_skbuff[entry]->tail),
 				     pkt_len,0);