wifi: rtw89: 8852b: add chip_ops related to BT coexistence

These chip_ops are used to assist BT coexistence module to control chip
specific operations, such as initial, pre-AGC, BT grant, set wifi priority
and tx power, RX gain, and get BT counter.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221009125403.19662-6-pkshih@realtek.com