mtd: rawnand: gpio: 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/20200519130035.1883-19-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/gpio.c

@@ -190,8 +190,12 @@ gpio_nand_get_io_sync(struct platform_device *pdev)
 static int gpio_nand_remove(struct platform_device *pdev)
 {
 	struct gpiomtd *gpiomtd = platform_get_drvdata(pdev);
+	struct nand_chip *chip = &gpiomtd->nand_chip;
+	int ret;
 
-	nand_release(&gpiomtd->nand_chip);
+	ret = mtd_device_unregister(nand_to_mtd(chip));
+	WARN_ON(ret);
+	nand_cleanup(chip);
 
 	/* Enable write protection and disable the chip */
 	if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp))