wifi: mac80211_hwsim: split bss_info_changed to vif/link info_changed

Replace the bss_info_changed callback with vif_cfg_changed
and link_info_changed callbacks (for vif changes and link
changes).

Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>