control: Alias TimerType locally

This is needed for a future commit that removes the local
phosphor::util::Timer implementation.

Tested:
    Built and run through unit tests.

Change-Id: I8ea3399fec8761055d4a0d94fb9ea91fd34040ea
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/control/zone.cpp b/control/zone.cpp
index 0050899..11246db 100644
--- a/control/zone.cpp
+++ b/control/zone.cpp
@@ -73,8 +73,7 @@
         // Start timer for fan speed decreases
         if (!_decTimer.running() && _decInterval != seconds::zero())
         {
-            _decTimer.start(_decInterval,
-                            util::Timer::TimerType::repeating);
+            _decTimer.start(_decInterval, TimerType::repeating);
         }
     }
 }
@@ -245,8 +244,7 @@
         }
         setSpeed(requestTarget);
         // Start timer countdown for fan speed increase
-        _incTimer.start(_incDelay,
-                        util::Timer::TimerType::oneshot);
+        _incTimer.start(_incDelay, TimerType::oneshot);
     }
 }