Minor refactoring in thresholds

No functional changes

Tested:
- All unit tests are passing

Signed-off-by: Krzysztof Grobelny <krzysztof.grobelny@intel.com>
Change-Id: I96360276cc7e7797a9e90a577804e94014e0bd91
diff --git a/src/utils/threshold_operations.hpp b/src/utils/threshold_operations.hpp
index 04b0195..99ae4a5 100644
--- a/src/utils/threshold_operations.hpp
+++ b/src/utils/threshold_operations.hpp
@@ -7,7 +7,7 @@
 struct ThresholdOperations
 {
     template <typename ThresholdType>
-    void initialize(ThresholdType* thresholdPtr)
+    static void initialize(ThresholdType* thresholdPtr)
     {
         for ([[maybe_unused]] auto& [sensor, detail] :
              thresholdPtr->sensorDetails)
@@ -18,7 +18,7 @@
     }
 
     template <typename ThresholdType>
-    typename ThresholdType::ThresholdDetail&
+    static typename ThresholdType::ThresholdDetail&
         getDetails(ThresholdType* thresholdPtr,
                    const interfaces::Sensor& sensor)
     {
@@ -30,7 +30,7 @@
     }
 
     template <typename ThresholdType>
-    void updateSensors(ThresholdType* thresholdPtr, Sensors newSensors)
+    static void updateSensors(ThresholdType* thresholdPtr, Sensors newSensors)
     {
         typename ThresholdType::SensorDetails newSensorDetails;
         typename ThresholdType::SensorDetails oldSensorDetails =