Input: wacom - add support for new LCD tablets

This adds support for the foolowing Wacom devices:

 - 0x9F - a single touch only LCD tablet;
 - 0xE2 - a two finger touch only LCD tablet;
 - 0xE3 -  a two finger touch, penabled LCD tablet.

Signed-off-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>