platform/x86: touchscreen_dmi: Add info for the Onda V820w tablet

Add touchscreen platform data for the Onda V820w tablet.

Signed-off-by: Jun Bo Bi <jambonmcyeah@gmail.com>
[andy: fixed compilation error, massaged commit message]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>