blk-throttle: Re-use the throtl_set_slice_end()

Re-use throtl_set_slice_end() to remove duplicate code.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-throttle.c

@@ -808,7 +808,7 @@ static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw,
 static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw,
 				       unsigned long jiffy_end)
 {
-	tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice);
+	throtl_set_slice_end(tg, rw, jiffy_end);
 	throtl_log(&tg->service_queue,
 		   "[%c] extend slice start=%lu end=%lu jiffies=%lu",
 		   rw == READ ? 'R' : 'W', tg->slice_start[rw],