ath79: ar934x: still advertise subpage on soft ecc

This sort of reverts Koen Vandeputte's commit
6561ca1 ("ath79: ar934x: fix mounting issues if subpage is not supported")

since it does not work on the MR18 as the UBI is coming from
Meraki in that way and it used to work with AR71XX before.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

target/linux/ath79/files/drivers/mtd/nand/raw/ar934x_nand.c

@@ -1325,10 +1325,10 @@ static int ar934x_nfc_attach_chip(struct nand_chip *nand)
 	if (ret)
 		return ret;
 
-	if (mtd->writesize == 2048)
-		nand->options |= NAND_NO_SUBPAGE_WRITE;
-
 	if (nand->ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST) {
+		if (mtd->writesize == 2048)
+			nand->options |= NAND_NO_SUBPAGE_WRITE;
+
 		ret = ar934x_nfc_setup_hwecc(nfc);
 		if (ret)
 			return ret;