Adding fmls instruction

Change-Id: Ia1752196fd50ade2c3160dc401a36618433420d8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/270822
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
3 files changed