[coreboot] Building Coreboot on ARM

[Paul Kocialkowski]

Just a quick announcement to let the community know that it is now possible to
build Coreboot on ARM (including building the toolchain).

I was able to produce bit-to-bit identical images from an x86 laptop and an ARM
laptop, which I find pretty cool!

This way, it's also possible to build Coreboot for an ARM-supported device on
that same device.

Cheers,