block: Drop unlikely before IS_ERR(_OR_NULL)

IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag,
so no need to do that again from its callers. Drop it.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-cgroup.c

@@ -881,7 +881,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 			blkg_free(new_blkg);
 		} else {
 			blkg = blkg_create(pos, q, new_blkg);
-			if (unlikely(IS_ERR(blkg))) {
+			if (IS_ERR(blkg)) {
 				ret = PTR_ERR(blkg);
 				goto fail_unlock;
 			}