sensors/zones: place in namespace and cleanup

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I527dbc8477a232945f696227a7b0b2adbee45175
diff --git a/pid/thermalcontroller.hpp b/pid/thermalcontroller.hpp
index 74e85ab..6144d49 100644
--- a/pid/thermalcontroller.hpp
+++ b/pid/thermalcontroller.hpp
@@ -7,6 +7,9 @@
 #include <string>
 #include <vector>
 
+namespace pid_control
+{
+
 /*
  * A ThermalController is a PID controller that reads a number of sensors and
  * provides the setpoints for the fans.
@@ -58,3 +61,5 @@
     std::vector<std::string> _inputs;
     ThermalType type;
 };
+
+} // namespace pid_control