Merge changes from topic 'wifi-aosp-master' into stage-aosp-master

* changes:
  Allow wificond to drop privileges after startup
  Allow wificond to set interfaces up and down
  Allow wificond to clean up wpa_supplicant state
  Allow wificond to drop signals on hostapd
  Give wificond permission to start/stop init services
  Give hostapd permissions to use its control socket
  Allow wificond to write wifi component config files
  add netlink socket permission for wificond
  SEPolicy to start hostapd via init
  Allow system_server to call wificond via Binder
  Allow wificond to mark interfaces up and down
  Separate permissions to set WiFi related properties
  Define explicit label for wlan sysfs fwpath
  sepolicy: Add permissions for wpa_supplicant binder
  sepolicy: add sepolicy binder support for wificond
  Sepolicy files for wificond