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.

[jkosina@suse.cz: microoptimize field->report->id to report->id]
Fixes: 14c9c014 ("HID: add vivaldi HID driver")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Stephen Boyd <swboyd@chromium.org> # CoachZ
Signed-off-by: Jiri Kosina <jkosina@suse.cz>