mx25_3ds: add mmc support

Update mx25_3ds board support to register esdhc device

Signed-off-by: Shawn Guo <shawn.gsc@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>