The MC13892 Analog-to-Digital input pins (ADIN5-7) are exposed on the
imx51-babbage board.

Pass the "fsl,mc13xxx-uses-adc" property so that the MC13892 ADC
block can work.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>