Add SPL options to tegra20 config files and enable SPL build for
tegra20 boards.  Also remove redundant code from u-boot that is not
contained in SPL.
Signed-off-by: NAllen Martin <amartin@nvidia.com>
Acked-by: NStephen Warren <swarren@wwwdotorg.org>
Tested-by: NThierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: NTom Warren <twarren@nvidia.com>