The CAM, meaning address CAM and bssid CAM here, will get leaks during
SER (system error recover) L2 reset process and ieee80211_restart_hw()
which is called by L2 reset process eventually.

The normal flow would be like
-> add interface (acquire 1)
-> enter ips (release 1)
-> leave ips (acquire 1)
-> connection (occupy 1) <(A) 1 leak after L2 reset if non-sec connection>

The ieee80211_restart_hw() flow (under connection)
-> ieee80211 reconfig
-> add interface (acquire 1)
-> leave ips (acquire 1)
-> connection (occupy (A) + 2) <(B) 1 more leak>

Originally, CAM is released before HW restart only if connection is under
security. Now, release CAM whatever connection it is to fix leak in (A).
OTOH, check if CAM is already valid to avoid acquiring multiple times to
fix (B).

Besides, if AP mode, release address CAM of all stations before HW restart.
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/20220314071250.40292-2-pkshih@realtek.com