rtw89: 8852c: set channel of MAC part

Configure channel and bandwidth of MAC registers to work properly.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220414062027.62638-11-pkshih@realtek.com