[VOL-3762] Updates to allow image download and update for the ONU

Change-Id: I0869307e3ef534c1d506b961d61a1ec6f5e13c2e
diff --git a/rw_core/mocks/adapter.go b/rw_core/mocks/adapter.go
index c01fc70..6710087 100644
--- a/rw_core/mocks/adapter.go
+++ b/rw_core/mocks/adapter.go
@@ -19,6 +19,7 @@
 import (
 	"context"
 	"fmt"
+	"github.com/opencord/voltha-protos/v4/go/extension"
 	"strconv"
 	"strings"
 	"sync"
@@ -267,6 +268,12 @@
 	return nil, nil
 }
 
+// Single_get_value_request retrieves a single value.
+func (ta *Adapter) Single_get_value_request(ctx context.Context, // nolint
+	request extension.SingleGetValueRequest) (*extension.SingleGetValueResponse, error) {
+	return nil, nil
+}
+
 // GetFlowCount returns the total number of flows presently under this adapter
 func (ta *Adapter) GetFlowCount() int {
 	ta.flowLock.RLock()