Revert rr271190, it was based on a misunderstanding.  The problem of
non-existant device<->xref info needs to be handled by creating the info,
which will come in a subsequent commit.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@271199 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f