Stop conflating F16 with linear gamma

Note to self: I debugged this, realized that the codecs
need to handle A2B -> XYZ, then realized that I just need
to wait for https://skia-review.googlesource.com/c/skia/+/136062

Bug: skia:
Change-Id: I594c22076feb3700b8a40c471a541fef5ff4e13e
Reviewed-on: https://skia-review.googlesource.com/137587
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
8 files changed