blk-iocost: remove duplicated lines in comments

Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NWeiping Zhang <zhangweiping@didiglobal.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-iocost.c

@@ -46,9 +46,6 @@
  * If needed, tools/cgroup/iocost_coef_gen.py can be used to generate
  * device-specific coefficients.
  *
- * If needed, tools/cgroup/iocost_coef_gen.py can be used to generate
- * device-specific coefficients.
- *
  * 2. Control Strategy
  *
  * The device virtual time (vtime) is used as the primary control metric.