NAND: Fix integer overflow in ONFI detection of chips >= 4GiB

This patch sync with David's patch on Linux in nand_flash_detect_onfi()

	commit 4ccb3b4497ce01fab4933704fe21581e30fda1a5
	Author: David Woodhouse <David.Woodhouse@intel.com>
	Date:   Fri Dec 3 16:36:34 2010 +0000

    	mtd: nand: Fix integer overflow in ONFI detection of chips >= 4GiB

    	Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: Florian Fainelli <florian@openwrt.org>

drivers/mtd/nand/nand_base.c

@@ -2482,7 +2482,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd,
 	mtd->writesize = le32_to_cpu(p->byte_per_page);
 	mtd->erasesize = le32_to_cpu(p->pages_per_block) * mtd->writesize;
 	mtd->oobsize = le16_to_cpu(p->spare_bytes_per_page);
-	chip->chipsize = le32_to_cpu(p->blocks_per_lun) * mtd->erasesize;
+	chip->chipsize = (uint64_t)le32_to_cpu(p->blocks_per_lun) * mtd->erasesize;
 	*busw = 0;
 	if (le16_to_cpu(p->features) & 1)
 		*busw = NAND_BUSWIDTH_16;