Add AVX2 version of ConvolveVertically

src/opts/SkOpts_hsw.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkOpts.h"
 
 #define SK_OPTS_NS hsw
+#include "SkBitmapFilter_opts.h"
 #include "SkRasterPipeline_opts.h"
 
 namespace SkOpts {
     void Init_hsw() {
         compile_pipeline = hsw::compile_pipeline;
+        convolve_vertically = hsw::convolve_vertically;
     }
 }