mtd: onenand: remove redundant mtd_device_unregister before onenand_release

onenand_release() will call mtd_device_unregister(), thus remove the redundant
mtd_device_unregister() call before onenand_release().

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Artem Bityutskiy <dedekind1@gmail.com>
diff --git a/drivers/mtd/onenand/generic.c b/drivers/mtd/onenand/generic.c
index 8152a31..7813095 100644
--- a/drivers/mtd/onenand/generic.c
+++ b/drivers/mtd/onenand/generic.c
@@ -97,7 +97,6 @@
 	platform_set_drvdata(pdev, NULL);
 
 	if (info) {
-		mtd_device_unregister(&info->mtd);
 		onenand_release(&info->mtd);
 		release_mem_region(res->start, size);
 		iounmap(info->onenand.base);