ARM: dts: msm: add touch device node

Add Synaptics touch controller device node. Touch
controller is connected to the host processor
via I2C.

Change-Id: Ie789f8cc1d1f7125f9e4b7fbc49a33f19e4a6a0f
Signed-off-by: Himanshu Aggarwal <haggarwa@codeaurora.org>