libvpx: Pull from upstream

source/libvpx/vpx_dsp/x86/subtract_sse2.asm

 ;
 ;  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.
 ;
-%define program_name vpx
 
 %include "third_party/x86inc/x86inc.asm"
 
 SECTION .text
 
 ; void vpx_subtract_block(int rows, int cols,
 ;                         int16_t *diff, ptrdiff_t diff_stride,
 ;                         const uint8_t *src, ptrdiff_t src_stride,
 ;                         const uint8_t *pred, ptrdiff_t pred_stride)
 
@@ skipping 98 matching lines @@
 .case_4:
   mov             pred_str, pred_stridemp
 .loop_4:
   loop_h
   lea                diffq, [diffq+diff_strideq*4]
   lea                 srcq, [srcq+src_strideq*2]
   lea                predq, [predq+pred_str*2]
   sub                rowsd, 2
   jg .loop_4
   RET