This adds the Gumstix DuoVero machine [1].  This is a OMAP4430-based
computer-on-module (COM aka SOM) that can be mounted on various
expansion boards with different peripherals.

[1] https://store.gumstix.com/index.php/category/43/Signed-off-by: NAsh Charles <ash@gumstix.com>
[trini: Rename gpmc_enable_gpmc_cs_config to gpmc_enable_gpmc_net_config]
Signed-off-by: NTom Rini <trini@ti.com>