USB: keyspan_pda: add new device id

Add USB VID/PID for Xircom PGMFHUB USB/serial component.  (The hub and SCSI
bridge on that hardware are recognized out of the box by existing drivers.)
Tested VID/PID using new_id and loopback connection and was met with
success, but that's all the testing done.

Signed-off-by: Nathaniel Wesley Filardo <nwf@cs.jhu.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>