CHROMIUM: ARM: dts: kitty: change touchscreen compatible

The elant touchscreen driver (elants_i2c.c) does not support
of_match_table thus i2c_device_id is used for device match.

Thus the compatible property of the touchscreen node should
start with "elan,elant2_i2c". This makes the corresponding
i2c_client has name as "elant2_i2c", which is same as in the
driver's i2c_device_id.

BUG=chrome-os-partner:34246
TEST=touchscreen works fine on kitty with factory image.

Change-Id: Ida97c3c57b18ab18d199b84e810fedaec04709cc
Signed-off-by: Ken Chang <kenc@nvidia.com>
Reviewed-on: https://chromium-review.googlesource.com/233083
Tested-by: Titan Lee <titanlee@nvidia.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
CHROMIUM: ARM: dts: kitty: change pwm period

Change the pwm frequency from 1KHz to 23KHz.

BUG=chrome-os-partner:34151
TEST=emerge-nyan_kitty, measure the pwm frequency.

Change-Id: Icb5b88d5fc82aed03c1c5818b96cf6d03e8c4edc
Signed-off-by: Ken Chang <kenc@nvidia.com>
Reviewed-on: https://chromium-review.googlesource.com/232178
Tested-by: Titan Lee <titanlee@nvidia.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
(cherry picked from commit c4b4c62852179285bda0ef2781b6f558d33ee5dd)
Reviewed-on: https://chromium-review.googlesource.com/232655