avoid need for -Wno-abi

GCC warns about ABI changes after GCC 4.6 that are moot
  1) because we're not supporting GCC 4.6;
  2) because we're force-inlining the function.

But because we're force-inlining, we can just as easily pass the U64
argument by pointer instead and get the same code generation.  This lets
us drop -Wno-abi.

Change-Id: Ia71379f7a23430a9b96b969783a0cef509821ae9
Reviewed-on: https://skia-review.googlesource.com/99742
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
3 files changed