mtd: mxc_nand: use 32bit copy functions

The following commit changes the function used to copy from/to
the hardware buffer to memcpy_[from|to]io. This does not work
since the hardware cannot handle the byte accesses used by these
functions. Instead of reverting this patch introduce 32bit
correspondents of these functions.

| commit 5775ba36ea9c760c2d7e697dac04f2f7fc95aa62
| Author: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
| Date:   Tue Apr 24 10:05:22 2012 +0200
|
|    mtd: mxc_nand: fix several sparse warnings about incorrect address space
|
|     Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
|     Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>