Convert IAAudioClient to AIDL

Bug: 160253486
Test: Manual testing using OboeTester
      Ran atest CtsNativeMediaAAudioTestCases
Change-Id: I18e6c03144c59ce78181abf7c509c21f2724ad22
diff --git a/services/oboeservice/AAudioService.h b/services/oboeservice/AAudioService.h
index caf48a5..8b16d37 100644
--- a/services/oboeservice/AAudioService.h
+++ b/services/oboeservice/AAudioService.h
@@ -49,7 +49,7 @@
 
     virtual status_t        dump(int fd, const Vector<String16>& args) override;
 
-    virtual void            registerClient(const sp<IAAudioClient>& client);
+    virtual void            registerClient(const sp<aaudio::IAAudioClient>& client);
 
     aaudio::aaudio_handle_t openStream(const aaudio::AAudioStreamRequest &request,
                                        aaudio::AAudioStreamConfiguration &configurationOutput)