Input: wacom - add Intuos5 Touch Ring/ExpressKey support

Intuos5 uses a new report type for Touch Ring and ExpressKey data.
Note that data from the capacitive sensors present on the ExpressKeys
will be ignored until a proper way is found to expose it.

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