block/bfq: fix ifdef for CONFIG_BFQ_GROUP_IOSCHED=y

commit 42b1bd33dcdef4ffd98f695e188bab82f9fa46d8 upstream.

Replace BFQ_GROUP_IOSCHED_ENABLED with CONFIG_BFQ_GROUP_IOSCHED.
Code under these ifdefs never worked, something might be broken.

Fixes: 0471559c ("block, bfq: add/remove entity weights correctly")
Reviewed-by: NHolger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

block/bfq-wf2q.c

@@ -1008,10 +1008,11 @@ static void __bfq_activate_entity(struct bfq_entity *entity,
 		entity->on_st = true;
 	}
 
-#ifdef BFQ_GROUP_IOSCHED_ENABLED
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
 	if (!bfq_entity_to_bfqq(entity)) { /* bfq_group */
 		struct bfq_group *bfqg =
 			container_of(entity, struct bfq_group, entity);
+		struct bfq_data *bfqd = bfqg->bfqd;
 
 		bfq_weights_tree_add(bfqg->bfqd, entity,
 				     &bfqd->group_weights_tree);