sdm845-common: Start using vendor_overlay

* This lets us override files in /vendor without
  relying on bind mounts ^.^

Change-Id: Ib0b173682a48836aeac97e2c3691176a44f13aab

sepolicy/private/file.te

@@ -18,6 +18,3 @@ type sysfs_oem, sysfs_type, fs_type;
 
 # data
 type display_misc_file, file_type, data_file_type, core_data_file_type;
-
-# system
-type system_configs_file, system_file_type, file_type;