Input: cm109 - do not stomp on control URB

We need to make sure we are not stomping on the control URB that was
issued when opening the device when attempting to toggle buzzer.
To do that we need to mark it as pending in cm109_open().

Reported-and-tested-by:  <syzbot+150f793ac5bc18eee150@syzkaller.appspotmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>