rtlwifi: btcoex: hook external functions for newer chips

Hook the external functions for newer ICs such as 8821a and 8192e.

Rename ex_halbtc8192e2ant_halt_notify to ex_btc8192e2ant_halt_notify.

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