[coreboot] Some updated instructions to flash coreboot to the Thinkpad X60 from vendor bios

[Peter Stuge]

Arthur Heymans wrote:
> https://gist.github.com/ArthurHeymans/c5ef494ada01af372735f237f6c6adbe

I note these differences from what I wrote up in the wiki:
(that may no longer be there though)

* CONFIG_BUCTS_BOOTBLOCK is now a thing (great! very neat!)
* updated flashrom patches
* use flashrom image file to not touch last 64k (great idea!)
* added nvramtool step

Is that accurate? Nice improvements for sure. Thanks.


//Peter