VOL-3766 : Support updating PM frequency.
Version updated to 4.0.6

Change-Id: I484aaabae2910ebf7b7423fb3ea80794ebe1f4c1
diff --git a/pkg/adapters/common/performance_metrics.go b/pkg/adapters/common/performance_metrics.go
index 6705c72..3b6d4f9 100644
--- a/pkg/adapters/common/performance_metrics.go
+++ b/pkg/adapters/common/performance_metrics.go
@@ -48,6 +48,11 @@
 	}
 }
 
+// UpdateFrequency will update the frequency.
+func (pm *PmMetrics) UpdateFrequency(frequency uint32) {
+	pm.frequency = frequency
+}
+
 func Metrics(pmNames []string) PmMetricsOption {
 	return func(args *PmMetrics) {
 		args.metrics = make(map[string]*voltha.PmConfig)