uboot-imx

NAND boot: fix nand_load overlap issue

The code copy data from NAND flash block by block, so when
the data length isn't a whole-number multiple of the block
size, it will overlap the rest space.

Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>