HID: wacom: Move handling of Intuos status packets to seperate function

In addition to the touchswitch state for "Intuos", these packets are
also sent by the Intuos Pro, Intuos5, and last-generation Bamboo
tablets when using a wired connection. They contain, among other
things, information about the optional wireless module and battery
charge state (to be supported in subsuquent patches).

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Acked-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>