Add SELinux policy for legacy permission service.

The updatable and non-updatable permission manager cannot share one
AIDL, so we need to create a new system service for the non-updatable
legacy one, and add the SELinux policy for it.

Bug: 158736025
Test: presubmit
Change-Id: Ief8da6335e5bfb17d915d707cf48f4a43332f6ae
diff --git a/private/service_contexts b/private/service_contexts
index 3788e55..91da637 100644
--- a/private/service_contexts
+++ b/private/service_contexts
@@ -127,6 +127,7 @@
 isub                                      u:object_r:radio_service:s0
 jobscheduler                              u:object_r:jobscheduler_service:s0
 launcherapps                              u:object_r:launcherapps_service:s0
+legacy_permission                         u:object_r:legacy_permission_service:s0
 lights                                    u:object_r:light_service:s0
 location                                  u:object_r:location_service:s0
 location_time_zone_manager                u:object_r:location_time_zone_manager_service:s0