camera2: Implement ICameraDeviceUser::waitUntilIdle

Also fixed some logging typo

Change-Id: Ib254bdb137dca10b12595c23aeb1c53097423425
diff --git a/services/camera/libcameraservice/photography/CameraDeviceClient.h b/services/camera/libcameraservice/photography/CameraDeviceClient.h
index c6c241a..bb2949c 100644
--- a/services/camera/libcameraservice/photography/CameraDeviceClient.h
+++ b/services/camera/libcameraservice/photography/CameraDeviceClient.h
@@ -87,6 +87,8 @@
     // -- Caller owns the newly allocated metadata
     virtual status_t      getCameraInfo(/*out*/CameraMetadata* info);
 
+    // Wait until all the submitted requests have finished processing
+    virtual status_t      waitUntilIdle();
     /**
      * Interface used by CameraService
      */