[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/autcpu12.c

@@ -154,6 +154,7 @@ int __init autcpu12_init(void)
 
 	/* Link the private data with the MTD structure */
 	autcpu12_mtd->priv = this;
+	autcpu12_mtd->owner = THIS_MODULE;
 
 	/* Set address of NAND IO lines */
 	this->IO_ADDR_R = autcpu12_fio_base;