[Linaro-validation] Lava-Lmp specification 0.1

Hi -

Here's a draft specification for some small, cheap hardware devices would be useful in Lava to solve many interesting test scenarios that can't be done without some small hardware assist.

I have some time to prototype these devices and scenario boards in the next couple of weeks, but before starting I would like to get feedback on the specification, particularly anything dumb ^^ or other interesting tests that are not mentioned that are compatible with the basic approach and could be piled on if thought about from the start.

Also, what is the status of the SD Mux thing currently? If it's moribund I can look at that too; if not, great.

-Andy