watchdog: Log watchdog updates for debug

Change-Id: Ida0a2f58e128d037fdbb5d94259f1637be67d8ae
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/watchdog.cpp b/watchdog.cpp
index d0dc7f0..8d5cbbe 100644
--- a/watchdog.cpp
+++ b/watchdog.cpp
@@ -79,6 +79,9 @@
         // Disable the timer
         timer.setEnabled<std::false_type>();
 
+        log<level::DEBUG>("watchdog: update time remaining",
+                         entry("INTERVAL=%llu", value));
+
         // Timer handles all in microseconds and hence converting
         auto usec = duration_cast<microseconds>(
                                   milliseconds(value));