automated: linux: add kselftest test

Kselftest test definitions detects pre-built tests on target rootfs.
if not found then, download kselftest and run tests.

Change-Id: Ie88860d79aef7cf7aa526f95f1f4803e30a4b899
Signed-off-by: Naresh Kamboju <naresh.kamboju@linaro.org>
2 files changed