wifi: rtw89: coex: Record down Wi-Fi initial mode information

This information will use as judgment about how to set RF/HW parameters.

Signed-off-by: Ching-Te Ku <ku920601@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20231218061341.51255-3-pkshih@realtek.com