When walking the tree yo find _PRT methods, check whether the device is actually enabled and functioning.  Similar to what we do for _INI.
When walking the tree yo find _PRT methods, check whether the device is
actually enabled and functioning.  Similar to what we do for _INI.

ok weingart@, beck@

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