mac80211: update bssid_indicator in ieee80211_assign_beacon

Update bssid_indicator in ieee80211_bss_conf according to the
number of bssid in the set.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/f92317e002fca9933f05a445fcefb4f53291d601.1645702516.git.lorenzo@kernel.org


Signed-off-by: Johannes Berg <johannes.berg@intel.com>