board: tbs2910: Add device tree

... as preparation for additional driver model coonversions.

We use CONFIG_OF_EMBED here to keep u-boot.imx as final binary name. So we
maintain compatibility with the original TBS u-boot and available HOWTOs
for u-boot updates.

Signed-off-by: Soeren Moch <smoch@web.de>
4 files changed