mtd: rawnand: oxnas: 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/20200519130035.1883-40-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/oxnas_nand.c

@@ -182,7 +182,8 @@ static int oxnas_nand_remove(struct platform_device *pdev)
 
 	for (i = 0; i < oxnas->nchips; i++) {
 		chip = oxnas->chips[i];
-		nand_release(chip);
+		WARN_ON(mtd_device_unregister(nand_to_mtd(chip)));
+		nand_cleanup(chip);
 	}
 
 	clk_disable_unprepare(oxnas->clk);