HID: vivaldi: fix handling devices not using numbered reports
Unfortunately details of USB HID transport bled into HID core and
handling of numbered/unnumbered reports is quite a mess, with
hid_report_len() calculating the length according to USB rules,
and hid_hw_raw_request() adding report ID to the buffer for both
numbered and unnumbered reports.
Untangling it all requres a lot of changes in HID, so for now let's
handle this in the driver.