HID: holtek: fix mouse probing

An overlook from the previous commit: we don't even parse or start the
device, meaning that the device is not presented to user space.

Fixes: 93020953

 ("HID: check for valid USB device for many HID drivers")
Cc: stable@vger.kernel.org
Link: https://bugs.archlinux.org/task/73048
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215341
Link: https://lore.kernel.org/r/e4efbf13-bd8d-0370-629b-6c80c0044b15@leemhuis.info/
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>