Remove SkNx AVX code. It is not really used. Getting in the way of refactoring.

src/core/SkOpts.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkOnce.h"
 #include "SkOpts.h"
 
@@ skipping 76 matching lines @@
     decltype(gray_to_RGB1)          gray_to_RGB1          = sk_default::gray_to_RGB1;
     decltype(grayA_to_RGBA)         grayA_to_RGBA         = sk_default::grayA_to_RGBA;
     decltype(grayA_to_rgbA)         grayA_to_rgbA         = sk_default::grayA_to_rgbA;
     decltype(inverted_CMYK_to_RGB1) inverted_CMYK_to_RGB1 = sk_default::inverted_CMYK_to_RGB1;
     decltype(inverted_CMYK_to_BGR1) inverted_CMYK_to_BGR1 = sk_default::inverted_CMYK_to_BGR1;
 
     // Each Init_foo() is defined in src/opts/SkOpts_foo.cpp.
     void Init_ssse3();
     void Init_sse41();
     void Init_sse42() {}
-    void Init_avx();
+    void Init_avx() {}
     void Init_avx2() {}
     void Init_neon();
 
     static void init() {
         // TODO: Chrome's not linking _sse* opts on iOS simulator builds.  Bug or feature?
     #if defined(SK_CPU_X86) && !defined(SK_BUILD_FOR_IOS)
         uint32_t abcd[] = {0,0,0,0};
         cpuid(abcd);
         if (abcd[2] & (1<< 9)) { Init_ssse3(); }
         if (abcd[2] & (1<<19)) { Init_sse41(); }
@@ skipping 20 matching lines @@
 
     SK_DECLARE_STATIC_ONCE(gInitOnce);
     void Init() { SkOnce(&gInitOnce, init); }
 
 #if SK_ALLOW_STATIC_GLOBAL_INITIALIZERS
     static struct AutoInit {
         AutoInit() { Init(); }
     } gAutoInit;
 #endif
 }