ubifs: Convert to use ERR_CAST()

As opposed to open-code, using the ERR_CAST macro clearly indicates that
this is a pointer to an error value and a type conversion was performed.

Signed-off-by: Shen Lichuan <shenlichuan@vivo.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Author: Shen Lichuan

fs/ubifs/lpt_commit.c

@@ -577,7 +577,7 @@ static struct ubifs_pnode *next_pnode_to_dirty(struct ubifs_info *c,
 	/* Go right */
 	nnode = ubifs_get_nnode(c, nnode, iip);
 	if (IS_ERR(nnode))
-		return (void *)nnode;
+		return ERR_CAST(nnode);
 
 	/* Go down to level 1 */
 	while (nnode->level > 1) {
@@ -594,7 +594,7 @@ static struct ubifs_pnode *next_pnode_to_dirty(struct ubifs_info *c,
 		}
 		nnode = ubifs_get_nnode(c, nnode, iip);
 		if (IS_ERR(nnode))
-			return (void *)nnode;
+			return ERR_CAST(nnode);
 	}
 
 	for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++)