When booting Chrome OS images the command line is stored separately from the kernel. Add a way to specify this address so that images boot correctly. Also add comments to the zimage.h header. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> [bmeng: adjust maxargs to 8 for 'zboot start'] Signed-off-by: Bin Meng <bmeng.cn@gmail.com>