Adding meta-raspberrypi as a platform

[Joel Stanley]

Hey Brad,

Jeremy came up with the interesting idea of enabling the raspberry pi
as a simple, cheap, easy to obtain development platform for OpenBMC.

The user story is: Bazza has a dev board on his desk and a spare
raspberry pi. He wants to give UART access and power control to a
colleague on the other side of the country so they can bring up the
NC-SI stack.

He could cook up something custom, but it turns out we have this sweet
project called OpenBMC that is designed for this task.

I've been toying with the meta-raspberrypi layer[1]. Can you help me
add that to our tree and have it build an image with the openbmc
userspace?

Cheers,

Joel

[1] http://git.yoctoproject.org/cgit/cgit.cgi/meta-raspberrypi