mpi3mr: Block devices persist despite being offlined during reset

The driver removes the drive from the OS if firmware sends 'device added'
event with hidden bit or inaccessible status.

Reviewed by: imp
Approved by: imp
Differential revision: https://reviews.freebsd.org/D44421

(cherry picked from commit 0d7056458db5b5dd7fdc5ccd8abab73e3ee76a20)