monitor: Change start/stop timer traces to DEBUG

These were put in to help debug an issue on the Rainier system.  Now
that that has been solved, change the traces to debug so they can can
still be turned on if necessary but don't show up during normal
operation.  How it is now, they typically show up around power offs at
the very least.

Change-Id: I291b0e0645c02142a89623b26c6ee1b0ff865529
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/monitor/tach_sensor.cpp b/monitor/tach_sensor.cpp
index 96fc06b..83285b9 100644
--- a/monitor/tach_sensor.cpp
+++ b/monitor/tach_sensor.cpp
@@ -239,7 +239,7 @@
 
     if (!timerRunning() || mode != _timerMode)
     {
-        log<level::INFO>(
+        log<level::DEBUG>(
             fmt::format("Start timer({}) on tach sensor {}. [delay = {}s]",
                         mode, _name,
                         duration_cast<seconds>(getDelay(mode)).count())
diff --git a/monitor/tach_sensor.hpp b/monitor/tach_sensor.hpp
index dc61074..0012a02 100644
--- a/monitor/tach_sensor.hpp
+++ b/monitor/tach_sensor.hpp
@@ -250,7 +250,7 @@
      */
     inline void stopTimer()
     {
-        phosphor::logging::log<phosphor::logging::level::INFO>(
+        phosphor::logging::log<phosphor::logging::level::DEBUG>(
             fmt::format("Stop running timer on tach sensor {}.", _name)
                 .c_str());
         _timer.setEnabled(false);