Move common/utils.go to device/utils.go.

The utility functions ConvB2S(), OnuToSn(), LoggerWithOnu() in common/utils.go strongly depend on ONU instance specification.
Then, I consider it should be in device package that contains ONU instance , not utils package.

Change-Id: I7fd2b21c5f7c51be8ec4a5c161da9c93e3a3f582
diff --git a/common/logger/logger.go b/common/logger/logger.go
index cb7229f..6efe0f1 100644
--- a/common/logger/logger.go
+++ b/common/logger/logger.go
@@ -17,9 +17,10 @@
 package logger
 
 import (
+	"time"
+
 	lkh "github.com/gfremex/logrus-kafka-hook"
 	log "github.com/sirupsen/logrus"
-	"time"
 )
 
 var (
@@ -34,17 +35,17 @@
 	myLogger = logger.WithField("topics", []string{"bbsim.log"})
 
 	var logLevel = log.DebugLevel
-	switch level{
-		case "TRACE":
-			logLevel = log.TraceLevel
-		case "INFO":
-			logLevel = log.InfoLevel
-		case "WARN":
-			logLevel = log.WarnLevel
-		case "ERROR":
-			logLevel = log.ErrorLevel
-		default:
-			logLevel = log.DebugLevel
+	switch level {
+	case "TRACE":
+		logLevel = log.TraceLevel
+	case "INFO":
+		logLevel = log.InfoLevel
+	case "WARN":
+		logLevel = log.WarnLevel
+	case "ERROR":
+		logLevel = log.ErrorLevel
+	default:
+		logLevel = log.DebugLevel
 	}
 	logger.Println("Setting Log Level ", logLevel)
 	logger.SetLevel(logLevel)
diff --git a/common/utils/utils.go b/common/utils/utils.go
deleted file mode 100644
index 3bfd0de..0000000
--- a/common/utils/utils.go
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * Copyright 2018-present Open Networking Foundation
-
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
-
- * http://www.apache.org/licenses/LICENSE-2.0
-
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package utils
-
-import (
-	"strconv"
-
-	"gerrit.opencord.org/voltha-bbsim/common/logger"
-	"gerrit.opencord.org/voltha-bbsim/device"
-	log "github.com/sirupsen/logrus"
-)
-
-// ConvB2S converts byte array to string
-func ConvB2S(b []byte) string {
-	s := ""
-	for _, i := range b {
-		s = s + strconv.FormatInt(int64(i/16), 16) + strconv.FormatInt(int64(i%16), 16)
-	}
-	return s
-}
-
-// OnuToSn returns serial number in string format for given ONU
-func OnuToSn(onu *device.Onu) string {
-	return string(onu.SerialNumber.VendorId) + ConvB2S(onu.SerialNumber.VendorSpecific)
-}
-
-// LoggerWithOnu method logs ONU fields
-func LoggerWithOnu(onu *device.Onu) *log.Entry {
-
-	if onu == nil {
-		logger.Warn("utils.LoggerWithOnu has been called without Onu")
-		return logger.GetLogger()
-	}
-
-	return logger.GetLogger().WithFields(log.Fields{
-		"serial_number": OnuToSn(onu),
-		"interfaceID":   onu.IntfID,
-		"onuID":         onu.OnuID,
-		"oltID":         onu.OltID,
-	})
-}