[SCSI] sas: unify the pointlessly separated enums sas_dev_type and sas_device_type

These enums have been separate since the dawn of SAS, mainly because the
latter is a procotol only enum and the former includes additional state
for libsas.  The dichotomy causes endless confusion about which one you
should use where and leads to pointless warnings like this:

drivers/scsi/mvsas/mv_sas.c: In function 'mvs_update_phyinfo':
drivers/scsi/mvsas/mv_sas.c:1162:34: warning: comparison between 'enum sas_device_type' and 'enum sas_dev_type' [-Wenum-compare]

Fix by eliminating one of them.  The one kept is effectively the sas.h
one, but call it sas_device_type and make sure the enums are all
properly namespaced with the SAS_ prefix.

Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/isci/task.c b/drivers/scsi/isci/task.c
index b6f19a1..9bb020a 100644
--- a/drivers/scsi/isci/task.c
+++ b/drivers/scsi/isci/task.c
@@ -250,7 +250,7 @@
 	}
 
 	/* XXX convert to get this from task->tproto like other drivers */
-	if (dev->dev_type == SAS_END_DEV) {
+	if (dev->dev_type == SAS_END_DEVICE) {
 		isci_tmf->proto = SAS_PROTOCOL_SSP;
 		status = sci_task_request_construct_ssp(ireq);
 		if (status != SCI_SUCCESS)