block: remove the error_sector argument to blkdev_issue_flush

The argument isn't used by any caller, and drivers don't fill out
bi_sector for flush requests either.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index bf5fcb4..629a56b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5256,7 +5256,7 @@ static int ext4_sync_fs(struct super_block *sb, int wait)
 		needs_barrier = true;
 	if (needs_barrier) {
 		int err;
-		err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
+		err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL);
 		if (!ret)
 			ret = err;
 	}