cfg80211: Move Multiple BSS info to struct cfg80211_bss to be visible

Previously the transmitted BSS and the non-trasmitted BSS list were
defined in struct cfg80211_internal_bss. Move them to struct cfg80211_bss
since mac80211 needs this info.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>