rtlwifi: rtl8192cu: Calculate descriptor checksum correctly for BE

This driver requires a checksum for the descriptors so that the wifi
chip is assured that the USB transmission was correct. These entries
are little-endian, but the driver was always using cpu order in the
calculation. As a result, the driver failed on BE hardware.
Signed-off-by: NLarry Finger <Larry.Finger@lwfinger.net>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c

@@ -477,14 +477,14 @@ static void _rtl_fill_usb_tx_desc(u8 *txdesc)
  */
 static void _rtl_tx_desc_checksum(u8 *txdesc)
 {
-	u16 *ptr = (u16 *)txdesc;
+	__le16 *ptr = (__le16 *)txdesc;
 	u16	checksum = 0;
 	u32 index;
 
 	/* Clear first */
 	SET_TX_DESC_TX_DESC_CHECKSUM(txdesc, 0);
 	for (index = 0; index < 16; index++)
-		checksum = checksum ^ (*(ptr + index));
+		checksum = checksum ^ le16_to_cpu(*(ptr + index));
 	SET_TX_DESC_TX_DESC_CHECKSUM(txdesc, checksum);
 }