mm: backing-dev: Remove the unneeded result variable

Return the value cgwb_bdi_init() directly instead of storing it in another
redundant variable.

Link: https://lkml.kernel.org/r/20220826071906.252419-1-ye.xingchen@zte.com.cn
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Reported-by: Zeal Robot <zealci@zte.com.cn>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/backing-dev.c

@@ -776,8 +776,6 @@ static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb)
 
 int bdi_init(struct backing_dev_info *bdi)
 {
-	int ret;
-
 	bdi->dev = NULL;
 
 	kref_init(&bdi->refcnt);
@@ -788,9 +786,7 @@ int bdi_init(struct backing_dev_info *bdi)
 	INIT_LIST_HEAD(&bdi->wb_list);
 	init_waitqueue_head(&bdi->wb_waitq);
 
-	ret = cgwb_bdi_init(bdi);
-
-	return ret;
+	return cgwb_bdi_init(bdi);
 }
 
 struct backing_dev_info *bdi_alloc(int node_id)