ARM: dts: logicpd-som-lv: Enable Touchscreen controller

The OMAP35 and DM3730 SOM-LV contains a TSC2004 touch screen
controller connected to I2C3. This patch adds support for this
controller.

Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>