use ZoneInterface pointers where Dbus aspect not important

The implementation of the ZoneInterface used is the DbusPidZone, however
using the ZoneInterface when the Dbus aspect is unimportant provides for
trivial support of other implementations.

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I0ed87322904e7f87e5b5c8a50c01144f3d843a10
diff --git a/pid/pidloop.hpp b/pid/pidloop.hpp
index c8365e3..0b8690b 100644
--- a/pid/pidloop.hpp
+++ b/pid/pidloop.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "pid/zone.hpp"
+#include "pid/zone_interface.hpp"
 
 #include <boost/asio/steady_timer.hpp>
 
@@ -12,12 +12,12 @@
  * This function calls itself indefinitely in an async loop to calculate
  * fan outputs based on thermal inputs.
  *
- * @param[in] zone - ptr to the DbusPidZone for this loop.
+ * @param[in] zone - ptr to the ZoneInterface implementation for this loop.
  * @param[in] timer - boost timer used for async callback.
  * @param[in] first - boolean to denote if initialization needs to be run.
  * @param[in] ms100cnt - loop timer counter.
  */
-void pidControlLoop(DbusPidZone* zone, boost::asio::steady_timer& timer,
+void pidControlLoop(ZoneInterface* zone, boost::asio::steady_timer& timer,
                     bool first = true, int ms100cnt = 0);
 
 } // namespace pid_control