rtlwifi: rtl8723ae: 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/rtl8723ae/trx.c

@@ -387,6 +387,11 @@ void rtl8723ae_tx_fill_desc(struct ieee80211_hw *hw,
 					    PCI_DMA_TODEVICE);
 	u8 bw_40 = 0;
 
+	if (pci_dma_mapping_error(rtlpci->pdev, mapping)) {
+		RT_TRACE(rtlpriv, COMP_SEND, DBG_TRACE,
+			 "DMA mapping error");
+		return;
+	}
 	if (mac->opmode == NL80211_IFTYPE_STATION) {
 		bw_40 = mac->bw_40;
 	} else if (mac->opmode == NL80211_IFTYPE_AP ||
@@ -542,6 +547,11 @@ void rtl8723ae_tx_fill_cmddesc(struct ieee80211_hw *hw,
 					    PCI_DMA_TODEVICE);
 	__le16 fc = hdr->frame_control;
 
+	if (pci_dma_mapping_error(rtlpci->pdev, mapping)) {
+		RT_TRACE(rtlpriv, COMP_SEND, DBG_TRACE,
+			 "DMA mapping error");
+		return;
+	}
 	CLEAR_PCI_TX_DESC_CONTENT(pdesc, TX_DESC_SIZE);
 
 	if (firstseg)