Input: wacom - add POINTER and DIRECT device properties

Adds INPUT_PROP_POINTER or INPUT_PROP_DIRECT as necessary to the
hardware supported by the Wacom driver. The DIRECT property is
assigned to devices with an embedded screen (i.e. touchscreens
and display tablets). The POINTER property is assigned to those
without embedded screens.

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Reviewed-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>