rtlwifi: btcoex: 21a 1ant: use default value when initiating coex

rtlwifi: btcoex: 21a 1ant: use default value when initiating coex

For newer coex mechanism, it is not necessary to set a critical value to
avoid the power on instability, just use default value for PTA.

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>