wifi: mac80211: fix multi-BSSID element parsing
When parsing a frame containing a multi-BSSID element, we
need to know both the transmitted and non-transmitted BSSID
so we can parse it correctly.
Unfortunately, in quite a number of cases, we got this wrong
and were passing the wrong BSSID or useless information:
* the mgmt->bssid from a frame is only the transmitted
BSSID if the frame is a beacon
* passing just one of the parameters as non-NULL isn't
useful and ignored
In those case where we need to parse for a specific BSS we
always have a BSS structure pointer, representing the BSS
we need, whether transmitted or not. Thus, pass that pointer
to the parsing function instead of the two BSSIDs.
Also fix two bugs:
* we need to re-parse all the elements for the other BSS
when iterating the non-transmitted BSSes in scan
* we need to parse for the correct BSS when setting up
the channel data in client code
Fixes: 78ac51f81532 ("mac80211: support multi-bssid")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>