[U-Boot] Does u-boot support nand flash boot

From the code we can know that u-boot didn't support boot from nand for smdk2410. If you want to do that you need to hack the code by yourself. It's not an hard task. You can look at the code under directory nand_spl for reference. In fact I'm doing it now, maybe next week I can work out the code and I'm glad to share the code with you.