block: wbt: Remove unnecessary invoking of wbt_update_limits in wbt_init

It's unnecessary to call wbt_update_limits explicitly within wbt_init,
because it will be called in the following function wbt_queue_depth_changed.
Signed-off-by: NLei Chen <lennychen@tencent.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-wbt.c

@@ -835,7 +835,6 @@ int wbt_init(struct request_queue *q)
 	rwb->enable_state = WBT_STATE_ON_DEFAULT;
 	rwb->wc = 1;
 	rwb->rq_depth.default_depth = RWB_DEF_DEPTH;
-	wbt_update_limits(rwb);
 
 	/*
 	 * Assign rwb and add the stats callback.