cris: nand: make use of mtd_to_nand() where appropriate

mtd_to_nand() was recently introduced to avoid direct accesses to the
mtd->priv field. Update all CRIS specific implementations to use this
helper.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

arch/cris/arch-v32/drivers/mach-a3/nandflash.c

@@ -52,7 +52,7 @@ static void crisv32_hwcontrol(struct mtd_info *mtd, int cmd,
 {
 	unsigned long flags;
 	reg_pio_rw_dout dout;
-	struct nand_chip *this = mtd->priv;
+	struct nand_chip *this = mtd_to_nand(mtd);
 
 	local_irq_save(flags);
 

arch/cris/arch-v32/drivers/mach-fs/nandflash.c

@@ -51,7 +51,7 @@ static void crisv32_hwcontrol(struct mtd_info *mtd, int cmd,
 {
 	unsigned long flags;
 	reg_gio_rw_pa_dout dout;
-	struct nand_chip *this = mtd->priv;
+	struct nand_chip *this = mtd_to_nand(mtd);
 
 	local_irq_save(flags);