HID: wacom: generic: read HID_DG_CONTACTMAX from any feature report

In the generic code path, HID_DG_CONTACTMAX was previously
only read from the second byte of report 0x23.

Another report (0x82) has the HID_DG_CONTACTMAX in the
higher nibble of the third byte. We should support reading the
value of HID_DG_CONTACTMAX no matter what report we are reading
or which position that value is in.

To do this we submit the feature report as a event report
using hid_report_raw_event(). Our modified finger event path
records the value of HID_DG_CONTACTMAX when it sees that usage.

Fixes: 8ffffd52

 ("HID: wacom: fix timeout on probe for some wacoms")
Signed-off-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>