wifi: rtw89: add mlo_dbcc_mode for WiFi 7 chips

WiFi 7 chips can operate in various MLO applications, such as 1 link (2SS)
and 2 links (1SS + 1SS), and we should configure different PHY mode for
each of them.

For example,
 - MLO_2_PLUS_0_1RF is 1 link with 2SS rate, and enable one RF component.
 - MLO_1_PLUS_1_1RF is 2 links with 1SS rate for each, and enable one RF
   component that can support two paths.

By default, we set the mode to legacy MLO_DBCC_NOT_SUPPORT (don't support
MLO and DBCC yet), and later we will introduce logic to change the mode.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240120003831.7014-2-pkshih@realtek.com