[media] em28xx: Add Terratec Cinergy HTC USB XS to em28xx-cards.c

This adds support for the Terratec Cinergy HTC USB XS which is similar to
the Terratec H5 by adding the USB-ids to the table. According to
http://linux.terratec.de it uses the same ICs and DVB-C works for me
using the firmware of the H5.

Signed-off-by: Holger Nelson <hnelson@hnelson.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>