[Linaro-validation] one build, many device_types

Hi,

We currently do a few builds in Linaro that can boot on a whole set of device_types.

Example: vexpress android can be build only once, but run in LAVA on vexpress-a9, -15, -TC2 and fastmodel XX,YY,ZZ, etc.

Unfortunately, we don't really support that use case very well in our CI so we end up submitting the artifact of a build to only one device_type automatically.

One approach to that problem would be to grow a feature in the scheduler to accept jobs that have a list of device_types in the job description.

Thoughts? Other ideas?