dm: core: Access device ofnode through functions

At present ofnode is present in the device even if it is never used. With
of-platdata this field is not used, so can be removed. In preparation for
this, change the access to go through inline functions.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/ata/mtk_ahci.c

@@ -68,7 +68,8 @@ static int mtk_ahci_parse_property(struct ahci_uc_priv *hpriv,
 				   SYS_CFG_SATA_MSK, SYS_CFG_SATA_EN);
 	}
 
-	ofnode_read_u32(dev->node, "ports-implemented", &hpriv->port_map);
+	ofnode_read_u32(dev_ofnode(dev), "ports-implemented",
+			&hpriv->port_map);
 	return 0;
 }