rtlwifi: Fix warning for unchecked pci_map_single() call

Kernel 3.8 implements checking of all DMA mapping calls and issues
a WARNING for the first it finds that is not checked.
Signed-off-by: NLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtlwifi/pci.c

@@ -743,6 +743,8 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
 
 done:
 		bufferaddress = (*((dma_addr_t *)skb->cb));
+		if (pci_dma_mapping_error(rtlpci->pdev, bufferaddress))
+			return;
 		tmp_one = 1;
 		rtlpriv->cfg->ops->set_desc((u8 *) pdesc, false,
 					    HW_DESC_RXBUFF_ADDR,
@@ -1115,6 +1117,10 @@ static int _rtl_pci_init_rx_ring(struct ieee80211_hw *hw)
 					   PCI_DMA_FROMDEVICE);
 
 			bufferaddress = (*((dma_addr_t *)skb->cb));
+			if (pci_dma_mapping_error(rtlpci->pdev, bufferaddress)) {
+				dev_kfree_skb_any(skb);
+				return 1;
+			}
 			rtlpriv->cfg->ops->set_desc((u8 *)entry, false,
 						    HW_DESC_RXBUFF_ADDR,
 						    (u8 *)&bufferaddress);