USB: ark3116 initialisation fix

This patch for the usb serial ark3116 driver fixes an initialisation
ordering bug that gets triggered on hotplug when using at least recent
debian/ubuntu userspace. Without it, ark3116 serial cables don't work.

Signed-off-by: Bart Hartgers <bart.hartgers@gmail.com>
Tested-by:  <law_ence.dev@ntlworld.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>