clamp to 1.0f in sk_linear_to_srgb_needs_round()

It's awkward today that it can go a little over 1.0f.
This is already slow, so a clamp won't slow it signficantly.

Change-Id: I9f882804e3ee949d72b7a05ad2cbac51731f6311
Reviewed-on: https://skia-review.googlesource.com/6617
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
1 file changed