rtlwifi: btcoex: Restore 23b 1ant routine for tdma adjustment

Routine btc8723b1ant_tdma_dur_adj_for_acl() was removed in a set of
Sparse fixes; however, this routine will be needed later.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
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>