mxc_nand: Do not do byte accesses to the NFC buffer.

This patch avoids byte access to the NFC buffer. Byte access to the
NFC is not allowed.

The patch is against linux-next 20100618.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>