[NETD-TC#11] Make TrafficController as libtraffic_controller into
Tethering module.

Delete tagSocket(), privilegedTagSocket() and untagSocket() since
they are moved out of TrafficController in aosp/1849156.

Bug: 202086915
Test: m; flash; boot;
Change-Id: Ifeaeb060fbf1add9f06748e7846b9e11e0345bda
5 files changed