ubifs: Fix missing error code err

Fix smatch warning:

fs/ubifs/journal.c:1610 ubifs_jnl_truncate() warn: missing error code
'err'
Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/journal.c

@@ -1607,6 +1607,7 @@ int ubifs_jnl_truncate(struct ubifs_info *c, const struct inode *inode,
 				ubifs_err(c, "bad data node (block %u, inode %lu)",
 					  blk, inode->i_ino);
 				ubifs_dump_node(c, dn, dn_size);
+				err = -EUCLEAN;
 				goto out_free;
 			}