remove sse4.1 opts level

This has become a weird target to optimize for.  It's not hugely better
than SSE2, and AVX2 is common nowadays, so SSE4.1's sweet spot is small.

Change-Id: I31c62fb371a4902f084f78309e7a43955f1fc0c2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/294320
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
2 files changed