blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL)

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

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Jens Axboe <axboe@fb.com>

include/linux/blk-cgroup.h

@@ -374,7 +374,7 @@ static inline struct request_list *blk_get_rl(struct request_queue *q,
 	 * root_rl in such cases.
 	 */
 	blkg = blkg_lookup_create(blkcg, q);
-	if (unlikely(IS_ERR(blkg)))
+	if (IS_ERR(blkg))
 		goto root_rl;
 
 	blkg_get(blkg);