Reland "Turn authpolicy on for everything except arm"

This reverts commit 07d815617bac726e70cb830d80c04dac8bb3eaaa.

Fixes a build breakage on x86-generic.

BUG=chromium:670430
TEST=Compiles on x86-generic

CQ-DEPEND=CL:416068, CL:416050

Change-Id: Ib7fb84304b225deb6dd7be6238c56fb39671fba3
Reviewed-on: https://chromium-review.googlesource.com/416049
Commit-Ready: Lutz Justen <ljusten@chromium.org>
Tested-by: Lutz Justen <ljusten@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
1 file changed