handle HSL case in HSLMatrix for skvm

Change-Id: I8316c0b813c93eb53eefd254f6e7db23295e7db5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/279416
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Reed <reed@google.com>
4 files changed