cciss: reinstate proper FIFO order of command queue list

Commit 8a3173de inadvertently changed the ordering when
switching to hlists. Change to regular list heads so we
can use tail list adds, this improves performance.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

drivers/block/cciss_cmd.h

@@ -195,7 +195,7 @@ typedef struct _CommandList_struct {
   int			   ctlr;
   int			   cmd_type; 
   long			   cmdindex;
-  struct hlist_node list;
+  struct list_head list;
   struct request *	   rq;
   struct completion *waiting;
   int	 retry_count;