meson support: remove code warnings 2

This commit contains code changes necessary to support the increased
warning level from Meson builds. Most changes are for unused variables.
to keep the review size manageable, this commit contains only control
changes (plus one in sensor-monitor).

Change-Id: Ie20f1d9028add4b605e4cc9fb230940710365706
Signed-off-by: Mike Capps <mikepcapps@gmail.com>
diff --git a/control/json/triggers/timer.cpp b/control/json/triggers/timer.cpp
index e04bdd0..ce8bba7 100644
--- a/control/json/triggers/timer.cpp
+++ b/control/json/triggers/timer.cpp
@@ -81,8 +81,9 @@
     return false;
 }
 
-enableTrigger triggerTimer(const json& jsonObj, const std::string& eventName,
-                           std::vector<std::unique_ptr<ActionBase>>& actions)
+enableTrigger
+    triggerTimer(const json& jsonObj, const std::string& /*eventName*/,
+                 std::vector<std::unique_ptr<ActionBase>>& /*actions*/)
 {
     // Get the type and interval of this timer from the JSON
     auto type = getType(jsonObj);