[SCSI] Remove host template ordered_flush variable

After the recent overhaul of the block layer the variable
"ordered_flush" is no longer used.
Signed-off-by: Tetsuo Takata <takatatt@intellilink.co.jp>
Signed-off-by: Jens Axboe <axboe@suse.de>

include/scsi/scsi_host.h

@@ -554,7 +554,6 @@ struct Scsi_Host {
 	/*
 	 * ordered write support
 	 */
-	unsigned ordered_flush:1;
 	unsigned ordered_tag:1;
 
 	/*