mtd: rawnand: mtk: Stop using nand_release()

This helper is not very useful and very often people get confused:
they use nand_release() instead of nand_cleanup().

Let's stop using nand_release() by calling mtd_device_unregister() and
nand_cleanup() directly.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200519130035.1883-29-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/mtk_nand.c

@@ -1578,13 +1578,18 @@ static int mtk_nfc_probe(struct platform_device *pdev)
 static int mtk_nfc_remove(struct platform_device *pdev)
 {
 	struct mtk_nfc *nfc = platform_get_drvdata(pdev);
-	struct mtk_nfc_nand_chip *chip;
+	struct mtk_nfc_nand_chip *mtk_chip;
+	struct nand_chip *chip;
+	int ret;
 
 	while (!list_empty(&nfc->chips)) {
-		chip = list_first_entry(&nfc->chips, struct mtk_nfc_nand_chip,
-					node);
-		nand_release(&chip->nand);
-		list_del(&chip->node);
+		mtk_chip = list_first_entry(&nfc->chips,
+					    struct mtk_nfc_nand_chip, node);
+		chip = &mtk_chip->nand;
+		ret = mtd_device_unregister(nand_to_mtd(chip));
+		WARN_ON(ret);
+		nand_cleanup(chip);
+		list_del(&mtk_chip->node);
 	}
 
 	mtk_ecc_release(nfc->ecc);