Add sepolicy for NNAPI AIDL HAL service

This is a shared part that all NN HAL users otherwise would have to
define themselves.

Bug: 172922059
Test: m
Test: VtsHalNeuralnetworksTest on master (locally)
Change-Id: I3616d0afbb115bc0feaed00488855646633da915
diff --git a/public/hal_neuralnetworks.te b/public/hal_neuralnetworks.te
index 228d990..416448a 100644
--- a/public/hal_neuralnetworks.te
+++ b/public/hal_neuralnetworks.te
@@ -28,3 +28,9 @@
 # This property is only expected to be found in /product/build.prop,
 # allow to be set only by init.
 neverallow { domain -init } nnapi_ext_deny_product_prop:property_service set;
+
+# Define sepolicy for NN AIDL HAL service
+hal_attribute_service(hal_neuralnetworks, hal_neuralnetworks_service)
+binder_call(hal_neuralnetworks_server, servicemanager)
+
+allow hal_neuralnetworks_server dumpstate:fifo_file write;