HID: wacom: rework fail path in probe() and parse_and_register()

Thanks to devres management, we don't need to remember a lot of failure
path. One or two is enough.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>