style: function names should be lower camel

Fix function names to be lower camel.

Change-Id: I145e1f4c03d7740bc1525dcffbdce2f78fd61075
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/pid/pidthread.hpp b/pid/pidthread.hpp
index 37c416a..94865c0 100644
--- a/pid/pidthread.hpp
+++ b/pid/pidthread.hpp
@@ -3,4 +3,4 @@
 #include "pid/zone.hpp"
 
 /* Given a zone, run through the loops. */
-void PIDControlThread(PIDZone* zone);
+void pidControlThread(PIDZone* zone);