The return code is not consistent with cli_simple_run_command_list(). For the
last command in a sequence, the return code is actually inverted.

Fix it.
Signed-off-by: Simon Glass <sjg@chromium.org>

Move these details from main (which doesn't care which parser is used) to
cli.c where they belong.
Signed-off-by: Simon Glass <sjg@chromium.org>

Add a bootretry_ prefix to these two functions, and remove the need for
the #ifdef around everything (it moves to the Makefile).
Signed-off-by: Simon Glass <sjg@chromium.org>

This code is only used by one board, so it seems a shame to clutter up
the readline code with it. Move it into its own file.
Signed-off-by: Simon Glass <sjg@chromium.org>

This makes it clear where the code resides.
Signed-off-by: Simon Glass <sjg@chromium.org>

It doesn't make sense to have the simple parser and the readline code
all in main. Split them out into separate files.
Signed-off-by: Simon Glass <sjg@chromium.org>