CHROMIUM: ARM: dts: kitty: add elan touchscreen controller

Add i2c node for elan touchscreen controller.

BUG=None
TEST=emerge-nyan_kitty chromeos-kernel-3_10 was successfully

Change-Id: I39a138db38ebec2f6b9de1b3c131924837d9ae3f
Signed-off-by: Penny Chiu <pchiu@nvidia.com>
Reviewed-on: https://chromium-review.googlesource.com/215804
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
(cherry picked from commit 867e1c3cd78b7aecc61747a7a4f6bced83f9d0f6)
Reviewed-on: https://chromium-review.googlesource.com/232896
Tested-by: Ken Chang <kenc@nvidia.com>
Commit-Queue: Ken Chang <kenc@nvidia.com>