[MTD] Fix module refcounting in NAND board drivers.

The _board_ driver needs to be mtd->owner, and it in turn pins the
nand.ko module. Fix them all to actually do that, and fix nand.ko not to
overwrite it -- and also to check that the caller sets it, if the caller
is a module.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/nand/rtc_from4.c

@@ -538,6 +538,7 @@ int __init rtc_from4_init(void)
 
 	/* Link the private data with the MTD structure */
 	rtc_from4_mtd->priv = this;
+	rtc_from4_mtd->owner = THIS_MODULE;
 
 	/* set area 5 as PCMCIA mode to clear the spec of tDH(Data hold time;9ns min) */
 	bcr1 = *SH77X9_BCR1 & ~0x0002;