[ARM64]: Fix ARM64 content_shell build

Currently there is no ARM64 support for seccomp_bpf and the content_shell build will fail without this check.

BUG=354405, 355125
R=jln@chromium.org, jochen@chromium.org

Review URL: https://codereview.chromium.org/331143002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@277622 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed