[SCSI] libsas: implement > 16 byte CDB support

Remove the arbitrary expectation in libsas that all SCSI commands are 16 bytes
or less.  Instead do all copies via cmd->cmd_len (and use a pointer to this in
the libsas task instead of a copy).  Note that this still doesn't enable > 16
byte CDB support in the underlying drivers because their internal format has
to be fixed and the wire format of > 16 byte CDBs according to the SAS spec is
different.  the libsas drivers (isci, aic94xx, mvsas and pm8xxx are all
updated for this change.

Cc: Lukasz Dorau <lukasz.dorau@intel.com>
Cc: Maciej Patelczyk <maciej.patelczyk@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Jack Wang <xjtuwjp@gmail.com>
Cc: Lindar Liu <lindar_liu@usish.com>
Cc: Xiangliang Yu <yuxiangl@marvell.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/aic94xx/aic94xx_task.c b/drivers/scsi/aic94xx/aic94xx_task.c
index 393e7ce..59b86e2 100644
--- a/drivers/scsi/aic94xx/aic94xx_task.c
+++ b/drivers/scsi/aic94xx/aic94xx_task.c
@@ -505,7 +505,8 @@
 		scb->ssp_task.ssp_cmd.efb_prio_attr |= EFB_MASK;
 	scb->ssp_task.ssp_cmd.efb_prio_attr |= (task->ssp_task.task_prio << 3);
 	scb->ssp_task.ssp_cmd.efb_prio_attr |= (task->ssp_task.task_attr & 7);
-	memcpy(scb->ssp_task.ssp_cmd.cdb, task->ssp_task.cdb, 16);
+	memcpy(scb->ssp_task.ssp_cmd.cdb, task->ssp_task.cmd->cmnd,
+	       task->ssp_task.cmd->cmd_len);
 
 	scb->ssp_task.sister_scb = cpu_to_le16(0xFFFF);
 	scb->ssp_task.conn_handle = cpu_to_le16(