mtd: add read_byte support to plat_nand

Lantiq SoCs have a External Bus Unit (EBU) that is used to attach MTD media.
As we need to co-exist with PCI on the same bus, certain swapping settings must
be applied. Similar to the NOR map driver we need to apply a fix to make NAND
work. The easiest way is to use byte reads.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 627f0c5..94a6679 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -654,6 +654,7 @@
 	void (*cmd_ctrl)(struct mtd_info *mtd, int dat, unsigned int ctrl);
 	void (*write_buf)(struct mtd_info *mtd, const uint8_t *buf, int len);
 	void (*read_buf)(struct mtd_info *mtd, uint8_t *buf, int len);
+	unsigned char (*read_byte)(struct mtd_info *mtd);
 	void *priv;
 };