mx31litekit: Fix boot with the new relocation scheme.

imx31_litekit has been converted to the new relocation scheme, but it does not boot.

Make the boot functional by using board_early_init_f .

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Tested-by: Magnus Lilja <lilja.magnus@gmail.com>