If _MIN > _MAX consider a WordBus resource to be invalid.  Fixes a panic on the IBM x3550-M4.
If _MIN > _MAX consider a WordBus resource to be invalid.  Fixes a panic on
the IBM x3550-M4.

ok mikeb@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars