Fix SEI CERT coding standard warnings

Change-Id: I47fdf29a50440c82fd9ccf111a846bf87e8a9e29
diff --git a/applications/message_handler_openamp/inference_runner.cpp b/applications/message_handler_openamp/inference_runner.cpp
index 2f9d8ec..00e95a9 100644
--- a/applications/message_handler_openamp/inference_runner.cpp
+++ b/applications/message_handler_openamp/inference_runner.cpp
@@ -148,7 +148,7 @@
     // Configure and enable events
     for (int i = 0; i < numEvents; i++) {
         ETHOSU_PMU_Set_EVTYPER(drv, i, static_cast<ethosu_pmu_event_type>(response->pmu_event_config[i]));
-        ETHOSU_PMU_CNTR_Enable(drv, 1 << i);
+        ETHOSU_PMU_CNTR_Enable(drv, 1u << i);
     }
 
     // Enable cycle counter