Fix an issue that caused Integrated RAID volumes on LSI mps(4) controllers
to not get scanned on boot.

The problem originated in change 253549.  With the change to the mps(4)
driver to scan only targets that it knows it has (as opposed to scanning
the entire bus), scanning RAID volumes on boot was omitted.

So, for versions of FreeBSD that have the scanning changes
(__FreeBSD_version 1000039 and higher), scan RAID volumes that are added
whether or not we're booting.

PR:		kern/181784
Reported by:	Xiguang Wang <kurapica@gmail.com>
Tested by:	Dennis Glatting <dg@pki2.com>
Sponsored by:	Spectra Logic
Approved by:	re (delphij)
MFC After:	3 days