rtw88: coex: Improve WLAN throughput when HFP COEX

Disable power save TDMA mechanism under HFP COEX, so WLAN can TX/RX full
time.

Signed-off-by: Ching-Te Ku <ku920601@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220215004855.4098-3-pkshih@realtek.com