uboot-phytec

tegra: move TEGRA_DEVICE_SETTINGS to tegra-common-post.h

Move environment settings for stdin/stdout/stderr to
tegra-common-post.h and generate them automaticaly based on input
device selection.

Signed-off-by: Allen Martin <amartin@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>