sepolicy: update access permissions for wigig property

system_app should have access to get_prop
persist.vendor.wigig.inwifi.enable to show the Wigig
enable toggle in WiFi Settings accordingly.
system_server should have read / write access to
persist.vendor.wigig.inwifi.sta.enable for keeping the
wigig STA enabled/disabled state.

Change-Id: Ia672a04721d9df4668e8310f81cf5bd413335c25