Use load value from CPU monitoring class.

ATxService/AutoTx.cs

@@ -532,7 +532,7 @@ namespace ATxService
 
             // check all system parameters for valid ranges and remember the reason in a string
             // if one of them is failing (to report in the log why we're suspended)
-            if (SystemChecks.GetCpuUsage() >= _config.MaxCpuUsage)
+            if (_cpu.Load() >= _config.MaxCpuUsage)
                 limitReason = "CPU usage";
             else if (SystemChecks.GetFreeMemory() < _config.MinAvailableMemory)
                 limitReason = "RAM usage";