GN: quiet link.exe warning spam.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4448

Change-Id: Iabc76cf111a62783770725a6cbf3a4284f35502b
Reviewed-on: https://skia-review.googlesource.com/4448
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
1 file changed