Camera2: remove waitUntilIdle from Camera2 API

Change-Id: Id034573d8b50aa0bc93bf7f0e776eb55316746ed
diff --git a/core/java/android/hardware/camera2/impl/CameraDevice.java b/core/java/android/hardware/camera2/impl/CameraDevice.java
index 40586f0..5ec01ad 100644
--- a/core/java/android/hardware/camera2/impl/CameraDevice.java
+++ b/core/java/android/hardware/camera2/impl/CameraDevice.java
@@ -351,8 +351,7 @@
         }
     }
 
-    @Override
-    public void waitUntilIdle() throws CameraAccessException {
+    private void waitUntilIdle() throws CameraAccessException {
 
         synchronized (mLock) {
             checkIfCameraClosed();