mtd: rawnand: au1550nd: 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/20200519130035.1883-3-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/au1550nd.c

@@ -325,8 +325,12 @@ static int au1550nd_remove(struct platform_device *pdev)
 {
 	struct au1550nd_ctx *ctx = platform_get_drvdata(pdev);
 	struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	struct nand_chip *chip = &ctx->chip;
+	int ret;
 
-	nand_release(&ctx->chip);
+	ret = mtd_device_unregister(nand_to_mtd(chip));
+	WARN_ON(ret);
+	nand_cleanup(chip);
 	iounmap(ctx->base);
 	release_mem_region(r->start, 0x1000);
 	kfree(ctx);