sensors/zones: place in namespace and cleanup

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I527dbc8477a232945f696227a7b0b2adbee45175
diff --git a/sysfs/sysfsread.cpp b/sysfs/sysfsread.cpp
index a070af2..eee1c8a 100644
--- a/sysfs/sysfsread.cpp
+++ b/sysfs/sysfsread.cpp
@@ -20,6 +20,9 @@
 #include <fstream>
 #include <iostream>
 
+namespace pid_control
+{
+
 ReadReturn SysFsRead::read(void)
 {
     int64_t value;
@@ -34,3 +37,5 @@
 
     return r;
 }
+
+} // namespace pid_control