wifi: rtw89: 8851b: add BT coexistence support function

Add 8851B specific parameters of BT coexistence. Since 8851B has special
two antenna hardware module with antenna diversity, BT coexistence needs
to recognize this, so add some fields to store these information for
further use.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230512061220.16544-4-pkshih@realtek.com