aspeed-soc: provide a framework to add new SoCs

aspeed-soc: provide a framework to add new SoCs

Let's define an object class for each Aspeed SoC we support. A
AspeedSoCInfo struct gathers the SoC specifications which can later be
used by an instance of the class or by a board using the SoC.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1473438177-26079-4-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>