This modifies the segment at 0x0 so that it contains enough of a fake
Extended BIOS Data Area at addresses 0x40e and 0x413 that Xen can
correctly locate its trampoline code.
Since custom Xen is no longer required, we can remove the module,
the patches and all of the references to it in the board definition
files.
if "CONFIG_TPM=y" is not present in the config file, functionalities
needing TPM could be disabled, while leaving other functionalities intact.
This will make Heads a more general-usage bootloader payload atop coreboot.
