[SCSI] libsas, aic94xx: fix dma mapping cockups with ATA

This one was noticed by Gilbert Wu of Adaptec:

The libata core actually does the DMA mapping for you, so there has to
be an exception in the device drivers that *don't* do dma mapping for
ATA commands.  However, since we've already done this, libsas must now
dma map any ATA commands that it wishes to issue ... and yes, this is a
horrible mess.

Additionally, the test in aic94xx for ATA protocols isn't quite right.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/aic94xx/aic94xx_task.c b/drivers/scsi/aic94xx/aic94xx_task.c
index 6c12c0f..d5d8cab 100644
--- a/drivers/scsi/aic94xx/aic94xx_task.c
+++ b/drivers/scsi/aic94xx/aic94xx_task.c
@@ -76,7 +76,7 @@
 
 	/* STP tasks come from libata which has already mapped
 	 * the SG list */
-	if (task->task_proto == SAS_PROTOCOL_STP)
+	if (sas_protocol_ata(task->task_proto))
 		num_sg = task->num_scatter;
 	else
 		num_sg = pci_map_sg(asd_ha->pcidev, task->scatter,
@@ -125,7 +125,7 @@
 
 	return 0;
 err_unmap:
-	if (task->task_proto != SAS_PROTOCOL_STP)
+	if (sas_protocol_ata(task->task_proto))
 		pci_unmap_sg(asd_ha->pcidev, task->scatter, task->num_scatter,
 			     task->data_dir);
 	return res;