wifi: mac80211: handle sdata->u.ap.active flag with MLO

wifi: mac80211: handle sdata->u.ap.active flag with MLO

Currently whenever link AP beacon is assigned, sdata->u.ap.active flag is
set and whenever it is brought down, the flag is reset. However, with MLO,
all the links of the same MLD would use the same sdata. Hence there is no
need to set/reset for each link up/down. Also, resetting it  when only one
of the links went down is not desirable.

Add changes to set the active flag only when first link is assigned
beacon. Similarly, add changes to reset that flag only when last link is
brought down.

Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>
Link: https://msgid.link/20240409094017.3165560-1-quic_adisi@quicinc.com
[remove unnecessary check before constant true assignment]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>