Expand UMV border to 96 pixels

Ensures that the full 64 pixel border is available for prediction (need a minimum of
64+INTERP_EXTEND on all sides, and 32+INTERP_EXTEND on UV). Value also must be a
multiple of 32 to keep UV stride alignment. The smaller border was causing the prediction
to read outside the frame, which can cause a mismatch.

TODO: Get rid of this explicit border and use edge emulation instead.

Change-Id: I3f68453a088ec0ab4349d0f5cc02b573be06d7c4

vpx_scale/yv12config.h

diff --git a/vpx_scale/yv12config.h b/vpx_scale/yv12config.h
index 14b6e27..22df399 100644
--- a/vpx_scale/yv12config.h
+++ b/vpx_scale/yv12config.h
@@ -18,7 +18,7 @@
 #include "vpx/vpx_integer.h"
 
 #define VP8BORDERINPIXELS       32
-#define VP9BORDERINPIXELS       64
+#define VP9BORDERINPIXELS       96
 #define VP9_INTERP_EXTEND        4
 
   /*************************************