x86: Add multiboot header

By adding a multiboot header, U-Boot can be loaded by GRUB2. Using GRUB2 to
bootstrap U-Boot is useful for using an existing BIOS to get an initial
U-Boot port up and running before implementing the low-level reset vector
code, SDRAM init, etc. and overwriting the BIOS

Signed-off-by: Graeme Russ <graeme.russ@gmail.com>
1 file changed