wifi: rtw89: reset AFEDIG register in power off sequence

Some Wi-Fi chips meet card lost issue due to unstable hardware signal of
GPIO pins during power off. Reset AFEDIG register before BB reset in
power off sequence could avoid unstable signal and fix the issue.

Signed-off-by: Chin-Yen Lee <timlee@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://msgid.link/20240426061200.44262-1-pkshih@realtek.com