uboot-imx

SMDK6400: Disable LED function in start.s on the nand booting

Since nand boot have some limit for the first 4KB, We only
disable the LED function to reduce the code space. At the
same time, Fix the compile error for LED function undefined
in the compile time of nand_spl.

Signed-off-by: Zhong Hongbo <bocui107@gmail.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>