Input: wacom - pass touch resolution to clients through input_absinfo

Also remove fake ABS_RX/ABS_RY "axes" that were used to report physical
dimensions now that we have better way.

Signed-off-by: Ping Cheng <pingc@wacom.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>