[Tether12] Give network stack permission for tetheroffload

Tethering module would run in network stack process. Add network_stack
as client of tetheroffload hidl and give it permission to create and share
netlink_netfilter_sockets

Bug: 144320246
Test: -build, flas, boot
      -OFF/ON hotspot

Change-Id: Id961fd4af0d30f902eb0115aa15db612aaa8bb91
diff --git a/private/network_stack.te b/private/network_stack.te
index 6db7d8f..e132840 100644
--- a/private/network_stack.te
+++ b/private/network_stack.te
@@ -70,3 +70,7 @@
 
 # Create/use netlink_tcpdiag_socket to get tcp info
 allow network_stack self:netlink_tcpdiag_socket { create_socket_perms_no_ioctl nlmsg_read nlmsg_write };
+############### Tethering Service app - Tethering.apk ##############
+hal_client_domain(network_stack, hal_tetheroffload)
+# Create and share netlink_netfilter_sockets for tetheroffload.
+allow network_stack self:netlink_netfilter_socket create_socket_perms_no_ioctl;