board: MCR3000: replace mtd->priv by mtd_to_nand()

Since commit 17cb4b8f32 ("mtd: nand: Add+use mtd_to/from_nand and
nand_get/set_controller_data"), mtd_to_nand() has to be used instead
of mtd->priv

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

board/cssi/MCR3000/nand.c

@@ -17,7 +17,7 @@
 
 static void nand_hwcontrol(struct mtd_info *mtdinfo, int cmd, unsigned int ctrl)
 {
-	struct nand_chip *this	= mtdinfo->priv;
+	struct nand_chip *this	= mtd_to_nand(mtdinfo);
 	immap_t __iomem *immr	= (immap_t __iomem *)CONFIG_SYS_IMMR;
 	unsigned short pddat	= 0;