None of our other fnmatch() calls make use of this, and the concept was
new to me at least. Given that this is only used for the recently added
SMBIOS field matches (and is not included in any release) let's disable
"extended" matches for now. We can certainly revisit this, and enable it
later if there is real demand, but if we do, we should probably add that
all over the place, not just for smbios matches.