Allow shell to set persist.logd.audit.rate

This can be useful, for both platform and app developers, when there
are lots of SELinux violations.

The property is only read by init, so no get_prop macros are needed.

Bug: 304313777
Test: set, `for x in $(seq 100); do ls /cache; done`, observe logs
Reference: Ib5352dcf3a85836ae5544c9feeb5222c97c50ecd
Change-Id: Ib23c008ed89e078a20ae136ba97e853f699e2050
diff --git a/private/property.te b/private/property.te
index 4f13338..b7ff516 100644
--- a/private/property.te
+++ b/private/property.te
@@ -27,6 +27,7 @@
 system_internal_prop(keystore_listen_prop)
 system_internal_prop(last_boot_reason_prop)
 system_internal_prop(localization_prop)
+system_internal_prop(logd_auditrate_prop)
 system_internal_prop(lower_kptr_restrict_prop)
 system_internal_prop(net_464xlat_fromvendor_prop)
 system_internal_prop(net_connectivity_prop)