ARM: mx28evk: Add I2C EEPROM support

mx28evk has a free slot U50 that can be used to populate an I2C EEPROM.

Add support for it.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>