[BLOCK] new block/ directory comment tidy

Some leftover comments referring to drivers/block that are now block/.
They don't add any information we don't already have, so kill them.
Signed-off-by: Coywolf Qi Hunt <qiyong@fc-cn.com>
Signed-off-by: Jens Axboe <axboe@suse.de>

block/as-iosched.c

 /*
- *  linux/drivers/block/as-iosched.c
- *
  *  Anticipatory & deadline i/o scheduler.
  *
  *  Copyright (C) 2002 Jens Axboe <axboe@suse.de>

block/cfq-iosched.c

 /*
- *  linux/drivers/block/cfq-iosched.c
- *
  *  CFQ, or complete fairness queueing, disk scheduler.
  *
  *  Based on ideas from a previously unfinished io

block/deadline-iosched.c

 /*
- *  linux/drivers/block/deadline-iosched.c
- *
  *  Deadline i/o scheduler.
  *
  *  Copyright (C) 2002 Jens Axboe <axboe@suse.de>

block/elevator.c

 /*
- *  linux/drivers/block/elevator.c
- *
  *  Block device elevator/IO-scheduler.
  *
  *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE

block/ll_rw_blk.c

 /*
- *  linux/drivers/block/ll_rw_blk.c
- *
  * Copyright (C) 1991, 1992 Linus Torvalds
  * Copyright (C) 1994,      Karl Keyte: Added support for disk statistics
  * Elevator latency, (C) 2000  Andrea Arcangeli <andrea@suse.de> SuSE