input: synaptics_dsx: Read touchscreen config-id during probe

Add support for reading configuration ID from the touch controller
during probe and print it. This is required to identify if touch
controller is programmed with correct touch firmware or not.

Change-Id: I155f0392ae67e5f9b184b9cef2a7bbb7666be30d
Signed-off-by: Sudhakar Manapati <smanap@codeaurora.org>
Signed-off-by: Himanshu Aggarwal <haggarwa@codeaurora.org>