[coreboot] Technologic TS-5300

[ron minnich]

you can't put more than 64k flash up in high memory on the ts5300 --
it's an sc520 limitation -- they drop 64k of hardware registers right
in the middle of what is supposed to be (by standard) BIOS ROM address
space. If you want to delete this code, be aware that you may be
removing sc520 flashing support completely. Absent a test, I recommend
you NOT delete it.

I think that for this type of change, you must be very very careful to
ensure it works before a commit. sc520 has very strange limitations. A
neat chip but I don't ever want to work with it again ...

ron