scsi: aacraid: Added macros to help loop through known buses and targets

Added macros to loop through the MAX SUPPORTED Buses and Targets. This
will make the code a bit easier to read.

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