rtlwifi: btcoex: 21a 2ant: refine tdma duration adjust function

1. Add more cases to adjust the wifi duration and add a case with
the max interval of 3 for some future uses.

2. rename tdma_adj -> ps_tdma_du_adj to indicate that this member is
for power saving tdma duration adjustment
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Pkshih <pkshih@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtc8821a2ant.h

@@ -87,8 +87,9 @@ struct coex_dm_8821a_2ant {
 	u8		pre_ps_tdma;
 	u8		cur_ps_tdma;
 	u8		ps_tdma_para[5];
-	u8		tdma_adj_type;
+	u8		ps_tdma_du_adj_type;
 	bool		reset_tdma_adjust;
+	bool		auto_tdma_adjust;
 	bool		pre_ps_tdma_on;
 	bool		cur_ps_tdma_on;
 	bool		pre_bt_auto_report;