Add a targeted interim perf suite for link devices.

TEST=site_utils/suite_scheduler/suite_scheduler.py -t,
site_utils/suite_enumerator.py -a . -l | grep link_perf
site_utils/suite_enumerator.py -a . link_perf
BUG=chromium-os:36357

Reviewed-on: https://gerrit.chromium.org/gerrit/38026
Tested-by: Scott Zawalski <scottz@chromium.org>
Reviewed-by: Alex Miller <milleral@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Reviewed-by: Scott Zawalski <scottz@chromium.org>
(cherry picked from commit 0dda41077147cfb411dabac963e41250d1e87cb8)

Change-Id: I844bd30db36719ba52fc48b6e825d2f5f3cca219
4 files changed