megaraid_sas: Code optimization build_and_issue_cmd return-type

build_and_issue_cmd should return SCSI_MLQUEUE_HOST_BUSY for a few error
cases instead of returning 1.

Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>