PID Objects & Algo

These are the PID controller implementations for fans,
and thermals.  This also includes the PID algorithm used.

Change-Id: I30471fbf7a8a7ed65f78bf105970d62815fedc56
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/pid/pidthread.hpp b/pid/pidthread.hpp
new file mode 100644
index 0000000..670d558
--- /dev/null
+++ b/pid/pidthread.hpp
@@ -0,0 +1,6 @@
+#pragma once
+
+#include "pid/zone.hpp"
+
+/* Given a zone, run through the loops. */
+void PIDControlThread(std::shared_ptr<PIDZone> zone);