Commit b69cc672 added support for the E-861.  After acquiring a C-867, I
realised that every Physik Instrumente's device has a different PID. They are
listed in the Windows device driver's .inf file. So here are all PIDs for the
current (and probably future) USB devices from Physik Instrumente.

Compiled, but only actually tested on the E-861 and C-867.
Signed-off-by: Éric Piel <piel@delmic.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>