[U-Boot] Adding support to Technexion TAM3517 SOM

[Stefano Babic]

This patches adds support for the Technexion's SOM TAM3517 based on
a TI AM3517. In agreement with Tapani Utrianen, this patchset superseeds
the recent patches sent to the ML by him with the same purpose.

This patchset requires the patchset for the AM3517 and EMAC posted
by Ilya Yanok, and not yet merged into mainline. Ilya's patches must be applied
first before this patchset.

[PATCH 1/2] ARM: omap3: added common configuration for Technexion
[PATCH 2/2] ARM: omap3: add support to Technexion twister board