netd: Enable clang-tidy and fix all warnings

Bug: 65246407
Test: m netd && system/netd/tests/runtests.sh
Change-Id: I1d22b2bc317fe7218ccde78859ed0623d6a1f8df
diff --git a/server/TrafficController.cpp b/server/TrafficController.cpp
index d6a6480..ff74ef6 100644
--- a/server/TrafficController.cpp
+++ b/server/TrafficController.cpp
@@ -580,7 +580,7 @@
     return StringPrintf("OK");
 }
 
-void dumpBpfMap(std::string mapName, DumpWriter& dw, const std::string& header) {
+void dumpBpfMap(const std::string& mapName, DumpWriter& dw, const std::string& header) {
     dw.blankline();
     dw.println("%s:", mapName.c_str());
     if(!header.empty()) {