wifi: rtw89: 8852b: turn off PoP function in monitor mode

PoP stands for Packet on Packet that can improve performance in noisy
environment, but it could get RX stuck suddenly. In normal mode, firmware
can help to resolve the stuck, but firmware doesn't work in monitor mode.
Therefore, turn off PoP to avoid RX stuck.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221125072416.94752-4-pkshih@realtek.com