Fix the GN rule of yasm for ChromeOS.

ChromeOS needs to run as linux here.

BUG=None
R=cmasone@chromium.org, hclam@chromium.org
TEST=manually

Review URL: https://codereview.chromium.org/627873002

Cr-Original-Commit-Position: refs/heads/master@{#298149}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: a59ce187e29beb8883ed211028f72557c7e4541b
1 file changed