Revert of add dummy avx file so xcode will build (patchset #1 id:1 of https://codereview.chromium.org/916563002/)

Reason for revert:
Going to punt on 16-bit float support for now.  Can't figure out ARM 64.

Original issue's description:
> add dummy avx file so xcode will build
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/a0921f2563701d54e4e022de99f2705f4ada8a6e

TBR=reed@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/912213002
2 files changed