scsi: mpi3mr: Enable STL on HBAs where multipath is disabled

Register the SAS, SATA devices to SCSI Transport Layer (STL) only if
multipath capability is disabled in the controller's firmware.

Link: https://lore.kernel.org/r/20220804131226.16653-9-sreekanth.reddy@broadcom.com
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>