Remove clamping of kPlus with F16 configs

The most common use-case for F16 is to draw things that are explicitly
outside of [0,1]. We can't prevent out-of-range values in general, users
could just draw out-of-range content in src mode. We've decided that
it's best to avoid surprising behavior, and trust the user in these
situations.

This effectively reverts https://skia-review.googlesource.com/c/skia/+/48183

Bug: skia:
Change-Id: I71c2dd925c567e2862d96ab70c752f19245a69c4
Reviewed-on: https://skia-review.googlesource.com/140500
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/src/gpu/effects/GrCoverageSetOpXP.cpp b/src/gpu/effects/GrCoverageSetOpXP.cpp
index 2524c9c..e7ac874 100644
--- a/src/gpu/effects/GrCoverageSetOpXP.cpp
+++ b/src/gpu/effects/GrCoverageSetOpXP.cpp
@@ -211,8 +211,7 @@
         const GrProcessorAnalysisColor&,
         GrProcessorAnalysisCoverage,
         bool hasMixedSamples,
-        const GrCaps& caps,
-        GrPixelConfigIsClamped dstIsClamped) const {
+        const GrCaps& caps) const {
     // We don't support inverting coverage with mixed samples. We don't expect to ever want this in
     // the future, however we could at some point make this work using an inverted coverage
     // modulation table. Note that an inverted table still won't work if there are coverage procs.