wifi: rtw89: chan: manage active interfaces

To set channel well for combination of MCC (multi-channel concurrency) and
impending MLO support, we need a method to manage relation between active
interfaces and channel contexts. If an interface owns at least one active
link, we call it an active interface. We add a list to manage active ones.

Basically, the list follows the active order except for the below case. To
be compatible with legacy behavior, the first interface that owns the first
channel context will put at the first entry in the list when recalculating.

Besides, MCC can also select and fill roles based on the above active list.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20241022083106.149252-4-pkshih@realtek.com