[SCSI] mpt2sas: Return the correct sense key for DIF errors

Only a target device should return ABORTED COMMAND when a PI error is
discovered. The HBA should always set the sense key to ILLEGAL REQUEST.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: "Sreekanth Reddy" <Sreekanth.reddy@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>