[coreboot] Need new type for CBFS

[ron minnich]

Definitely don't use NULL for anything -- it's a free space marker as
patrick points out.

The type is actually
        unsigned int type;

I would make the following proposal: we reserve the range 0-255 for
cbfs "system" (i.e. coreboot) use and open up the rest of the range
for any other use. Then we allow people to register types on the wiki
in some way.

I can't believe coreboot will ever need more than 256 types, and I
can't believe the community will ever need more than 16M.

ron