mx6sxsabresd: Remove unneeded board_late_init()

Since commit 1f98e31b ("imx: mx6sxsabresd: Use the pfuze common init
function") board_late_init() became empty, so we can safely remove this unneeded
function.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>