rtl8xxxu: TX RTS rate is word 4 for 8723a

Correct the setting of TX RTS for 8723a generation chips. In addition
update documentation to match that this is part of data word 4, note
data word 5.
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.c

@@ -7084,7 +7084,8 @@ static void rtl8xxxu_tx(struct ieee80211_hw *hw,
 
 	if (rate_flag & IEEE80211_TX_RC_USE_RTS_CTS) {
 		/* Use RTS rate 24M - does the mac80211 tell us which to use? */
-		tx_desc->txdw4 |= cpu_to_le32(DESC_RATE_24M);
+		tx_desc->txdw4 |= cpu_to_le32(DESC_RATE_24M <<
+					      TXDESC_RTS_RATE_SHIFT_8723A);
 		tx_desc->txdw4 |= cpu_to_le32(TXDESC_RTS_CTS_ENABLE_8723A);
 		tx_desc->txdw4 |= cpu_to_le32(TXDESC_HW_RTS_ENABLE_8723A);
 	}

drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h

@@ -475,6 +475,8 @@ struct rtl8723bu_tx_desc {
 #define TXDESC_SEQ_MASK_8723A		0x0fff0000
 
 /* Word 4 */
+#define TXDESC_RTS_RATE_SHIFT_8723A	0
+#define TXDESC_RTS_RATE_MASK_8723A	0x3f
 #define TXDESC_QOS			BIT(6)
 #define TXDESC_HW_SEQ_ENABLE_8723A	BIT(7)
 #define TXDESC_USE_DRIVER_RATE_8723A	BIT(8)
@@ -496,8 +498,6 @@ struct rtl8723bu_tx_desc {
 #define TXDESC_RTS_RATE_MASK_8723B	0x3f000000
 
 /* Word 5 */
-#define TXDESC_RTS_RATE_SHIFT_8723A	0
-#define TXDESC_RTS_RATE_MASK_8723A	0x3f
 #define TXDESC_SHORT_GI			BIT(6)
 #define TXDESC_CCX_TAG			BIT(7)
 #define TXDESC_RETRY_LIMIT_ENABLE_8723A	BIT(17)