Add support for Leon touch devices, which is the same as
slippy/falco/peppy/wolf on the same buses using the LynxPoint-LP I2C via
the i2c-designware-pci driver.
Based on the following patch:
https://chromium-review.googlesource.com/#/c/168351/
Signed-off-by: Gene Chen <gene.chen@intel.com> Reviewed-by: Benson Leung <bleung@chromium.org> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Signed-off-by: Olof Johansson <olof@lixom.net>