wifi: rtw89: rfk: rename rtw89_mcc_info to rtw89_rfk_mcc_info

The `rtw89_mcc_info mcc` is only for RFK MCC stuffs instead of common
MCC management info. Replace it with `rtw89_rfk_mcc_info rfk_mcc` to
avoid confusion and reserve `struct rtw89_mcc_info mcc` for MCC management
code.

(No logic changes.)

Signed-off-by: Zong-Zhe Yang <kevin_yang@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/20221129083130.45708-2-pkshih@realtek.com