[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>
diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
index 338fda8..f800259 100644
--- a/drivers/mtd/nand/s3c2410.c
+++ b/drivers/mtd/nand/s3c2410.c
@@ -516,6 +516,7 @@
 
 	nmtd->info	   = info;
 	nmtd->mtd.priv	   = chip;
+	nmtd->mtd.owner    = THIS_MODULE;
 	nmtd->set	   = set;
 
 	if (hardware_ecc) {