scsi: aacraid: Use hotplug handling function in place of scsi_scan_host

Driver uses scsi_scan_host to add new devices in the driver init path,
which adds all the fw exposed devices. The drivers resorts to queue
command checks to block out commands to _hidden_ devices.

Use the hotplug handler code to add new devices during driver init and
other areas, this is only for safw. For ARC scsi_scan_host will still
apply.

Signed-off-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>