The SDP4430 does not have onboard NAND, it has eMMC on the second
MMC slot.  This patch adds support for saving the u-boot environment
to eMMC.
Signed-off-by: NAneesh V <aneesh@ti.com>
Signed-off-by: NSukumar Ghorai <s-ghorai@ti.com>
Tested-by: NSteve Sakoman <steve@sakoman.com>