Add kernel_CrosECSysfs to verify sysfs interface to EC

This checks that the sysfs interface to the Chrome OS EC is working. The
test just ensures that the latest attributes are present and providing
semi-useful data. We don't try to confirm the actual data, since that can
vary widely between systems, just that *something* is readable without errors.

BUG=chromium:334014
TEST=Uh, it's a test. Run it.

Change-Id: Ic12ea8a393c6d5f95901ecfa4fa1041bce7c3932
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/182654
2 files changed