Enable LnbCallback in hidl/aidl default tuner implementation

Bug: 210960436
Test: cts.TunerTest#testLnbAddAndRemoveSharee
Change-Id: I11443144dcd1979afe9b077c446faaa293ccb61c
diff --git a/tv/tuner/aidl/default/Lnb.h b/tv/tuner/aidl/default/Lnb.h
index bfe3097..464f9a4 100644
--- a/tv/tuner/aidl/default/Lnb.h
+++ b/tv/tuner/aidl/default/Lnb.h
@@ -44,6 +44,7 @@
   private:
     int mId;
     virtual ~Lnb();
+    std::shared_ptr<ILnbCallback> mCallback;
 };
 
 }  // namespace tuner