mtd: nand: Fix memory allocation in nanddev_bbt_init()

Fix the size of the buffer allocated to store the in-memory BBT.
This bug was previously hidden by a different bug, that was fixed in
commit d098093ba06e ("mtd: nand: Fix nanddev_neraseblocks()").

Fixes: 9c3736a3de21 ("mtd: nand: Add core infrastructure to deal with NAND devices")
Cc: <[e-mail]>
Signed-off-by: Frieder Schrempf <[e-mail]>
Acked-by: Miquel Raynal <[e-mail]>
Signed-off-by: Boris Brezillon <[e-mail]>

drivers/mtd/nand/bbt.c

···
 	unsigned int nwords = DIV_ROUND_UP(nblocks * bits_per_block,
 					   BITS_PER_LONG);
 
-	nand->bbt.cache = kzalloc(nwords, GFP_KERNEL);
+	nand->bbt.cache = kcalloc(nwords, sizeof(*nand->bbt.cache),
+				  GFP_KERNEL);
 	if (!nand->bbt.cache)
 		return -ENOMEM;