audio: Use ChildInterface in StreamCommonImpl

Replace the pair of 'shared_ptr<>, Binder' with
the equivalent ChildInterface.

Fix logging of returned sub-objects to print their
Binder value instead of the local pointer.

Bug: 264712385
Test: m
Change-Id: I1350e7b3720c6244cd8527e1d021ee9577399291
diff --git a/audio/aidl/default/ModulePrimary.cpp b/audio/aidl/default/ModulePrimary.cpp
index cbb6730..f66da37 100644
--- a/audio/aidl/default/ModulePrimary.cpp
+++ b/audio/aidl/default/ModulePrimary.cpp
@@ -38,7 +38,8 @@
         mTelephony = ndk::SharedRefBase::make<Telephony>();
     }
     *_aidl_return = mTelephony.getPtr();
-    LOG(DEBUG) << __func__ << ": returning instance of ITelephony: " << _aidl_return->get();
+    LOG(DEBUG) << __func__
+               << ": returning instance of ITelephony: " << _aidl_return->get()->asBinder().get();
     return ndk::ScopedAStatus::ok();
 }