config_distro_bootcmd.h defines a common boot environment for multiple
platforms, including several environment variables that are intended for
interactive use by an end-user.  Document which variables are considered
public interfaces that must remain compatible in future u-boot versions.
Signed-off-by: NKarsten Merker <merker@debian.org>
Acked-by: NStephen Warren <swarren@nvidia.com>

Add documentation on how to setup a system to use the generic distro
configs and boot commands. This spells out what is needed to make a
system conformant, but does not limit the board to only the defaults.
Signed-off-by: NDennis Gilmore <dennis@ausil.us>
[swarren, added concept, user config, BOOT_TARGET_DEVICES sections.
edited the rest]
Signed-off-by: NStephen Warren <swarren@nvidia.com>