Allow an empty ROM to be created, without needing to provide a descriptor.
The descriptor is not needed on some x86 boards.
Signed-off-by: Simon Glass <sjg@chromium.org>
Newer Intel chips require a Management Engine which requires a particular
format for the SPI flash that contains the boot loader. Add a tool that
supports creating and modifying these ROM images.
This tool is from Chrome OS but has been cleaned up to use U-Boot style
and to add comments. A few features have been added also.
Signed-off-by: Simon Glass <sjg@chromium.org>