Prevent VP8 encoding crash

This commit changes the value of highbitdepth flag to avoid conflict
with vp8 refresh_last_frame flag.

Change-Id: Idcff2cf44f0a200bd935b326f785c0cf32d7228a
diff --git a/vpx_scale/yv12config.h b/vpx_scale/yv12config.h
index 6cdc235..76cf771 100644
--- a/vpx_scale/yv12config.h
+++ b/vpx_scale/yv12config.h
@@ -61,7 +61,7 @@
   int flags;
 } YV12_BUFFER_CONFIG;
 
-#define YV12_FLAG_HIGHBITDEPTH 1
+#define YV12_FLAG_HIGHBITDEPTH 8
 
 int vp8_yv12_alloc_frame_buffer(YV12_BUFFER_CONFIG *ybf,
                                 int width, int height, int border);