sensors/zones: place in namespace and cleanup

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I527dbc8477a232945f696227a7b0b2adbee45175
diff --git a/sensors/manager.hpp b/sensors/manager.hpp
index 740ef00..6fcd275 100644
--- a/sensors/manager.hpp
+++ b/sensors/manager.hpp
@@ -10,6 +10,9 @@
 #include <string>
 #include <vector>
 
+namespace pid_control
+{
+
 /*
  * The SensorManager holds all sensors across all zones.
  */
@@ -61,3 +64,5 @@
 
     static constexpr auto SensorRoot = "/xyz/openbmc_project/extsensors";
 };
+
+} // namespace pid_control