[VOL-3085]Implement UpdatePmConfig api for voltha-openolt-adapter

Change-Id: Id1f2ae30d7f0d8f4aa4516b96809cf4a1e116dd1
diff --git a/internal/pkg/core/openolt.go b/internal/pkg/core/openolt.go
index 36a609e..3704945 100644
--- a/internal/pkg/core/openolt.go
+++ b/internal/pkg/core/openolt.go
@@ -289,7 +289,12 @@
 
 //Update_pm_config returns PmConfigs nil or error
 func (oo *OpenOLT) Update_pm_config(device *voltha.Device, pmConfigs *voltha.PmConfigs) error {
-	return olterrors.ErrNotImplemented
+	logger.Debugw("Update_pm_config", log.Fields{"device-id": device.Id, "pm-configs": pmConfigs})
+	if handler := oo.getDeviceHandler(device.Id); handler != nil {
+		handler.UpdatePmConfig(pmConfigs)
+		return nil
+	}
+	return olterrors.NewErrNotFound("device-handler", log.Fields{"device-id": device.Id}, nil)
 }
 
 //Receive_packet_out sends packet out to the device