Fix transfer function epsilon

This has never worked.
1.0f == 1.0f + FLT_MIN

BUG=skia:

Change-Id: I73c8f321ea0d13497cb74f7bd5965d5910e664d1
Reviewed-on: https://skia-review.googlesource.com/9280
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed