mtd: rawnand: vf610: 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>
Cc: Stefan Agner <stefan@agner.ch>
Link: https://lore.kernel.org/linux-mtd/20200519130035.1883-60-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/vf610_nfc.c

@@ -917,8 +917,12 @@ static int vf610_nfc_probe(struct platform_device *pdev)
 static int vf610_nfc_remove(struct platform_device *pdev)
 {
 	struct vf610_nfc *nfc = platform_get_drvdata(pdev);
+	struct nand_chip *chip = &nfc->chip;
+	int ret;
 
-	nand_release(&nfc->chip);
+	ret = mtd_device_unregister(nand_to_mtd(chip));
+	WARN_ON(ret);
+	nand_cleanup(chip);
 	clk_disable_unprepare(nfc->clk);
 	return 0;
 }