block: Consolidate phys_segment and hw_segment limits

Except for SCSI no device drivers distinguish between physical and
hardware segment limits.  Consolidate the two into a single segment
limit.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index d04ea9a..f67d1a1 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -3983,8 +3983,7 @@
 		return -ENODEV;
 	}
 
-	i = min(queue_max_hw_segments(SDp->request_queue),
-		queue_max_phys_segments(SDp->request_queue));
+	i = queue_max_segments(SDp->request_queue);
 	if (st_max_sg_segs < i)
 		i = st_max_sg_segs;
 	buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);