Load default environment into /default

Load the built-in default environment and the env partition in NOR flash
into /default and /env, respectively. Previously, we loaded the built-in
default environment into /env if the env partition in the NOR was
corrupted.

Run /default/bin/init instead of /env/bin/init.

The command "saveenv" writes files under /env into the env partition in
NOR flash.

The static built-in environment ensures consistent behavior across
units. Developers still have the chance to customize barebox' behavior
by storing files in /env. Subsequent commits will add hooks to the
default environment that execute scripts in /env.

Change-Id: Idbcaaab56ca860768ef0e0a0955d75e5e38364b3
6 files changed