scsi: megaraid_sas: Retry with reduced queue depth when alloc fails for higher QD

scsi: megaraid_sas: Retry with reduced queue depth when alloc fails for higher QD

In certain cases, the host memory is limited and with FW supporting
higher queue depths there are increasing chances of IO request frame
allocation failures that we are seeing. In case of request frame
allocation failures, retry allocation with reduced queue depth (in steps
of 64) to continue to configure the controller with a reduced
performance rather than failing load.

Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>