ANativeWindow: fix up some comments

This change clarifies in the ANativeWindow perform docs which perform calls are
private to the framework and should not be made by code below the HAL level.

Change-Id: Ibfeba0760d9a3f74996e6358d5ad89a408f80dfe
diff --git a/include/system/window.h b/include/system/window.h
index 89720d5..1a036df 100644
--- a/include/system/window.h
+++ b/include/system/window.h
@@ -427,19 +427,20 @@
      *     NATIVE_WINDOW_SET_USAGE
      *     NATIVE_WINDOW_CONNECT               (deprecated)
      *     NATIVE_WINDOW_DISCONNECT            (deprecated)
-     *     NATIVE_WINDOW_SET_CROP
+     *     NATIVE_WINDOW_SET_CROP              (private)
      *     NATIVE_WINDOW_SET_BUFFER_COUNT
      *     NATIVE_WINDOW_SET_BUFFERS_GEOMETRY  (deprecated)
      *     NATIVE_WINDOW_SET_BUFFERS_TRANSFORM
      *     NATIVE_WINDOW_SET_BUFFERS_TIMESTAMP
      *     NATIVE_WINDOW_SET_BUFFERS_DIMENSIONS
      *     NATIVE_WINDOW_SET_BUFFERS_FORMAT
-     *     NATIVE_WINDOW_SET_SCALING_MODE
+     *     NATIVE_WINDOW_SET_SCALING_MODE       (private)
      *     NATIVE_WINDOW_LOCK                   (private)
      *     NATIVE_WINDOW_UNLOCK_AND_POST        (private)
      *     NATIVE_WINDOW_API_CONNECT            (private)
      *     NATIVE_WINDOW_API_DISCONNECT         (private)
      *     NATIVE_WINDOW_SET_BUFFERS_USER_DIMENSIONS (private)
+     *     NATIVE_WINDOW_SET_ACTIVE_RECT        (private)
      *
      */