[coreboot] Kconfig suggestion

[ron minnich]

Would be interesting, for working targets, to create a defconfig in
the mainboard directory for that target. Then, as each mainboard is
tested and known-good in Kconfig, people (and an automated tool) could
easily see that we had a Kconfig-supported mainboard.

We could then define some threshhold (80%? 90%? 95%? ) at which the
remaining mainboards would have to "convert or die" :-)

I can see a day when the targets directory goes away, along with the
old config tool! Oh happy day!

ron