uboot-imx

travis-ci: set env vars to name jobs

Travis CI names sub-jobs after the first environment variable that is set
for a script. This doesn't produce meaningful results for any of the non-
buildman jobs. Add a dummy variable to give the jobs meaningful names.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Tom Rini <trini@konsulko.com>