When we steal memory, return the VA for the memory that we have stolen and not the memory prior to it.
When we steal memory, return the VA for the memory that we have stolen and
not the memory prior to it.

Lots of help from oga@

ok kettenis@

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