ubifs: Fix error return code in alloc_wbufs()

Fix to return PTR_ERR() error code from the error handling case instead
fo 0 in function alloc_wbufs(), as done elsewhere in this function.

Fixes: 6a98bc46 ("ubifs: Add authentication nodes to journal")
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/super.c

@@ -838,8 +838,10 @@ static int alloc_wbufs(struct ubifs_info *c)
 		c->jheads[i].wbuf.jhead = i;
 		c->jheads[i].grouped = 1;
 		c->jheads[i].log_hash = ubifs_hash_get_desc(c);
-		if (IS_ERR(c->jheads[i].log_hash))
+		if (IS_ERR(c->jheads[i].log_hash)) {
+			err = PTR_ERR(c->jheads[i].log_hash);
 			goto out;
+		}
 	}
 
 	/*