wifi: rtw89: fw: add definition of H2C command and C2H event for MRC series

For Wi-Fi 7 chips, FW supports MRC (multi-role concurrent) functions
including H2C commands and C2H events. We can consider FW MRC functions
as a superset of FW MCC (multi-channel concurrent) functions. And, MRC
functions can take MLO things into account.

Basically before MLO, SW can also manipulate FW MRC to work original
SW MCC flow. So, we add them first and implement the handling in the
following. And then, SW MCC will call different series of FW functions
according to chip later.

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://msgid.link/20240213073514.23796-2-pkshih@realtek.com