Add a new event that is triggered in main_loop() before
autoboot_command(). This allows platform code to provide a custom
bootcmd string via the event system.
The event uses struct event_bootcmd which provides a buffer for the
bootcmd string and its size. Platform event handlers can write their
custom bootcmd to this buffer.
Co-developed-by: Claude <noreply@anthropic.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
69891885b7