[media] em28xx: Better support for the Terratec Cinergy HTC USB XS

This intializes the card just like the windows driver does

- the "HTC USB XS HD" uses the same firmware as the "HTC Stick HD";
- both have different GPIO and reg init sequences;

Tested only with DVB-C.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>