Add sepolicy for mmd system properties

mmd uses "mmd." and "persist.device_config.mmd_native." prefixed system
properties to configure itself.

Bug: 375431994
Test: manual

Change-Id: Idf7c8d4f1a314595cd75d494f8a55a3d26773514
diff --git a/private/mmd.te b/private/mmd.te
index 4e49519..d299bd8 100644
--- a/private/mmd.te
+++ b/private/mmd.te
@@ -7,6 +7,7 @@
 
 # Set mmd.enabled_aconfig properties.
 set_prop(mmd, mmd_prop)
+get_prop(mmd, device_config_mmd_native_prop)
 
 # mmd binder setup
 add_service(mmd, mmd_service)