sensors/zones: place in namespace and cleanup

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I527dbc8477a232945f696227a7b0b2adbee45175
diff --git a/sensors/builder.cpp b/sensors/builder.cpp
index 1cea61a..8a1f54a 100644
--- a/sensors/builder.cpp
+++ b/sensors/builder.cpp
@@ -35,13 +35,12 @@
 #include "sysfs/sysfswrite.hpp"
 #include "util.hpp"
 
+namespace pid_control
+{
+
 static constexpr bool deferSignals = true;
 static DbusHelper helper;
 
-using ::pid_control::getReadInterfaceType;
-using ::pid_control::getWriteInterfaceType;
-using ::pid_control::IOInterfaceType;
-
 SensorManager
     buildSensors(const std::map<std::string, struct conf::SensorConfig>& config,
                  sdbusplus::bus::bus& passive, sdbusplus::bus::bus& host)
@@ -186,3 +185,5 @@
 
     return mgmr;
 }
+
+} // namespace pid_control