Remove assert from powf_

This assert is being hit on some builders, likely from the call to
  powf_(tf->a * x + tf->b, tf->g)
inside skcms_TransferFunction_eval.

Rather than patch up this powf_ call, change powf_ to return 0 for
negative inputs. This allows us to remove the powf_(fmaxf_) pattern
from skcms_TFType_PQish.

Bug: chromium:333638402
Change-Id: I6edc8af2818a1252fb88d5da89f91ee25e285247
Reviewed-by: Brian Osman <>
Reviewed-by: Christopher Cameron <>
Commit-Queue: Christopher Cameron <>
1 file changed