rtlwifi: btcoexist: Fix breakage of ant_sel for rtl8723be

In commit bcd37f4a ("rtlwifi: btcoex: 23b 2ant: let bt transmit when
hw initialisation done"), there is an additional error when the module
parameter ant_sel is used to select the auxilary antenna. The error is
that the antenna selection is not checked when writing the antenna
selection register.

Fixes: bcd37f4a ("rtlwifi: btcoex: 23b 2ant: let bt transmit when hw initialisation done")
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Cc: Stable <stable@vger.kernel.org> # 4.12+
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtc8723b2ant.c

@@ -1183,7 +1183,10 @@ static void btc8723b2ant_set_ant_path(struct btc_coexist *btcoexist,
 		}
 
 		/* fixed internal switch S1->WiFi, S0->BT */
-		btcoexist->btc_write_4byte(btcoexist, 0x948, 0x0);
+		if (board_info->btdm_ant_pos == BTC_ANTENNA_AT_MAIN_PORT)
+			btcoexist->btc_write_2byte(btcoexist, 0x948, 0x0);
+		else
+			btcoexist->btc_write_2byte(btcoexist, 0x948, 0x280);
 
 		switch (antpos_type) {
 		case BTC_ANT_WIFI_AT_MAIN: