USB: ftdi driver - add support for optical probe device

Added support for the Elster Unicom III Optical Probe.
The device ID has already been added to the usb.ids file.

Cc: stable <stable@kernel.org>
Signed-off-by: Ed Beroset <beroset@mindspring.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>