Update mps(4) via 8-STABLE

Since we ship an updated mfi(4) from 8-STABLE, it may be meaningful
to also suck in the updates to the HBA-only models from LSI.
(some HBA/RAID cards are cross-flashable between operational modes)

While this doesn't explicitely add new hardware support, changelogs indicate
bug fixes like memory leaks one may be happy to see in production.

As with mfi(3) this wraps all changes into one large patch obtained
from cherry picks via 8-STABLE applied on a clean 8.3-RELENG branch.

See the readme to get an idea what is included (hopefully helpful for later merges)
Merge pull request #71 from matsimon/mps-8STABLE

Update mps(4) via 8-STABLE