mtd: rawnand: diskonchip: 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: NMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200519130035.1883-14-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/diskonchip.c

@@ -1514,13 +1514,16 @@ static void release_nanddoc(void)
 	struct mtd_info *mtd, *nextmtd;
 	struct nand_chip *nand;
 	struct doc_priv *doc;
+	int ret;
 
 	for (mtd = doclist; mtd; mtd = nextmtd) {
 		nand = mtd_to_nand(mtd);
 		doc = nand_get_controller_data(nand);
 
 		nextmtd = doc->nextdoc;
-		nand_release(nand);
+		ret = mtd_device_unregister(mtd);
+		WARN_ON(ret);
+		nand_cleanup(nand);
 		iounmap(doc->virtadr);
 		release_mem_region(doc->physadr, DOC_IOREMAP_LEN);
 		free_rs(doc->rs_decoder);