mtd: oxnas_nand: Allocating more than necessary in probe()

We only need to allocate sizeof(struct oxnas_nand_ctrl) which is 192
bytes and not sizeof(struct nand_chip) which is a much larger 3056
bytes.

Fixes: 668592492409 ("mtd: nand: Add OX820 NAND Support")
Signed-off-by: Dan Carpenter <[e-mail]>
Acked-by: Neil Armstrong <[e-mail]>
Acked-by: Boris Brezillon <[e-mail]>
Signed-off-by: Brian Norris <[e-mail]>

drivers/mtd/nand/oxnas_nand.c

···
 	int err = 0;
 
 	/* Allocate memory for the device structure (and zero it) */
-	oxnas = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
+	oxnas = devm_kzalloc(&pdev->dev, sizeof(*oxnas),
 			     GFP_KERNEL);
 	if (!oxnas)
 		return -ENOMEM;