Update libvpx snapshot to v0.9.7-p1 (Cayuga).

source/libvpx/vpx_scale/yv12config.h

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 41 matching lines @@
         unsigned char *y_buffer;
         unsigned char *u_buffer;
         unsigned char *v_buffer;
 
         unsigned char *buffer_alloc;
         int border;
         int frame_size;
         YUV_TYPE clrtype;
 
         int corrupted;
+        int flags;
     } YV12_BUFFER_CONFIG;
 
     int vp8_yv12_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf, int width, int height, int border);
     int vp8_yv12_de_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf);
 
 #ifdef __cplusplus
 }
 #endif
 
 
 #endif /*YV12_CONFIG_H*/