staging: erofs: switch to ->iterate_shared()

After commit 6192269444 ("introduce a parallel variant of ->iterate()"),
readdir can be done without taking exclusive inode lock of course.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/erofs/dir.c

@@ -142,6 +142,6 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
 const struct file_operations erofs_dir_fops = {
 	.llseek		= generic_file_llseek,
 	.read		= generic_read_dir,
-	.iterate	= erofs_readdir,
+	.iterate_shared	= erofs_readdir,
 };