Add target_arch=arm64 support.

Currently only adding jsimd_none.c to get things building.

BUG=354405
R=wangxianzhu@chromium.org

Review URL: https://codereview.chromium.org/210933002

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/libjpeg_turbo@259566 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/libjpeg.gyp b/libjpeg.gyp
index 1d9a9a7..3f6b07b 100644
--- a/libjpeg.gyp
+++ b/libjpeg.gyp
@@ -180,6 +180,11 @@
             }]
           ],
         }],
+        [ 'target_arch=="arm64"', {
+          'sources': [
+            'jsimd_none.c',
+          ],
+        }],
         [ 'target_arch=="mipsel"', {
           'sources': [
             'jsimd_none.c',