mtd: jz4780_nand: remove useless mtd->priv = chip assignment

As of commit 2d3b77bac3 ("mtd: nand: update mtd_to_nand()"), this
assignment isn't necessary, since struct mtd_info is embedded in struct
nand_chip.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Harvey Hunt <harvey.hunt@imgtec.com>
Cc: Alex Smith <alex@alex-smith.me.uk>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/jz4780_nand.c

@@ -270,7 +270,6 @@ static int jz4780_nand_init_chip(struct platform_device *pdev,
 
 	chip = &nand->chip;
 	mtd = nand_to_mtd(chip);
-	mtd->priv = chip;
 	mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%s.%d", dev_name(dev),
 				   cs->bank);
 	if (!mtd->name)