mx27: mxt_td60: Add support to SD/MMC

This patch configures iomux and i2c io expander in order to add
support to SD/MMC cards on i-MXT TD60.

Signed-off-by: Alan Carvalho de Assis <acassis@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>