wifi: rtw89: coex: move chip_ops::btc_bt_aci_imp to a generic code

This chunk is to set fixed BT LNA2 at level5 when WiFi/BT shared BTG RFC
to improve BT anti-interference ability from adjacent channel. Since all
chips use the same setting, remove chip_ops::btc_bt_aci_imp.

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/20221005083212.45683-2-pkshih@realtek.com