HID: wacom: Support 2nd-gen Intuos Pro's Bluetooth classic interface

In addition to its USB interface, the second-generation Intuos Pro
includes a Bluetooth radio that offers two pairing interfaces: classic
and low-energy. The classic interface functions just like the earlier
Bluetooth-enabled Intuos4 and Graphire4 tablets, appearing as a HID device
that our driver can work with. The low-energy interface is intented to
be used by userspace applications that make use of its paper-to-digital
capabilities.

Despite the USB interface using Wacom's new vendor-defined HID usages,
the Bluetooth interface provides us with useless black-box "blob"
report descriptors like past devices. We thus have to explicitly add
support for the PIDs and reports used.

These devices pack a /lot/ of information into a single Bluetooth
input report. Each report contains up to seven snapshots of the pen
state, four snapshots of the touch state (of five touches each), pad
state, and battery data. Thankfully this isn't too hard for the driver
to report -- it just takes a fair amount of code to extract!

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Reviewed-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>