wifi: rtw89: coex: Add LPS protocol radio state for RTL8852B

This LPS state will not turn off RF, and it can still do some basic
traffic, only RTL8852B has the state. Coexistence need let Bluetooth
know WiFi is still alive to prevent some Bluetooth performance issue.

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/20230314020617.28193-2-pkshih@realtek.com