wifi: rtw89: coex: Limit Wi-Fi scan slot cost to avoid A2DP glitch

wifi: rtw89: coex: Limit Wi-Fi scan slot cost to avoid A2DP glitch

When Wi-Fi is scanning at 2.4GHz, PTA will abort almost all the BT request.
Once the Wi-Fi slot stay too long, BT audio device can not get enough data,
audio glitch will happened. This patch limit 2.4Ghz Wi-Fi slot to 80ms
while Wi-Fi is scanning to avoid audio glitch.

Signed-off-by: Ching-Te Ku <ku920601@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250819034428.26307-5-pkshih@realtek.com