Bug 1659274 - silence build warnings in SWGL linear_composite. r=jimb
Bug 1659274 - silence build warnings in SWGL linear_composite. r=jimb

Differential Revision: https://phabricator.services.mozilla.com/D87181

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/01c8bc283e34f95f3550eb0641a3c82fdef7c443

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender