[VOL-936] add changes for onu distance from OLT

Change-Id: If6201799946ac753780d0424c4bd986e2fb394d2
diff --git a/rw_core/mocks/adapter.go b/rw_core/mocks/adapter.go
index 6a8fb22..e14457d 100644
--- a/rw_core/mocks/adapter.go
+++ b/rw_core/mocks/adapter.go
@@ -259,3 +259,7 @@
 func (ta *Adapter) Start_omci_test(device *voltha.Device, request *voltha.OmciTestRequest) (*voltha.TestResponse, error) { //nolint
 	return nil, nil
 }
+
+func (ta *Adapter) Get_ext_value(deviceId string, device *voltha.Device, valueflag voltha.ValueType_Type) (*voltha.ReturnValues, error) { //nolint
+	return nil, nil
+}