Add MSA optimized ARGB scaling functions

BUILD.gn

 # Copyright 2014 The LibYuv 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.
 
 import("libyuv.gni")
 import("//testing/test.gni")
@@ skipping 146 matching lines @@
       cflags = [ "-mfpu=neon" ]
     }
   }
 }
 
 if (libyuv_use_msa) {
   static_library("libyuv_msa") {
     sources = [
       # MSA Source Files
       "source/row_msa.cc",
+      "source/scale_msa.cc",
     ]
 
     public_configs = [ ":libyuv_config" ]
   }
 }
 
 if (libyuv_include_tests) {
   config("libyuv_unittest_warnings_config") {
     if (!is_win) {
       cflags = [
@@ skipping 118 matching lines @@
   }
 
   executable("cpuid") {
     sources = [
       # sources
       "util/cpuid.c"
     ]
     deps = [ ":libyuv" ]
   }
 }