mtd: nand: remove useless mtd->priv = chip assignments

mtd_to_nand() now uses the container_of() approach to transform an
mtd_info pointer into a nand_chip one. Drop useless mtd->priv
assignments from NAND controller drivers.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/fsl_upm.c

@@ -176,7 +176,6 @@ static int fun_chip_init(struct fsl_upm_nand *fun,
 	if (fun->rnb_gpio[0] >= 0)
 		fun->chip.dev_ready = fun_chip_ready;
 
-	mtd->priv = &fun->chip;
 	mtd->dev.parent = fun->dev;
 
 	flash_np = of_get_next_child(upm_np, NULL);