drop GaussNewton to max 3 parameters

Change-Id: I8e59aa2e1821704d2ed344b41684ed544861346e
Reviewed-on: https://skia-review.googlesource.com/124080
Commit-Queue: Mike Klein <mtklein@chromium.org>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Mike Klein <mtklein@chromium.org>
Reviewed-by: Brian Osman <brianosman@google.com>
6 files changed