wifi: rtw89: 8922a: add set_channel BB part

In additional to configure band, channel and bandwidth registers, it also
configure CCK support on 2GHZ band, spur elimination, and RX gain.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240215055741.14148-3-pkshih@realtek.com