scsi: aacraid: Create helper functions to get lun info

Created inline function to retrieve lun info for each device from the
phy luns structure.

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