V4L/DVB (5491): Cx88: Support the DTV1000 T analog inputs

Add support for the S-Video and CVBS (composite) analog video inputs
of the Leadtek WinFast DTV1000 T adapter.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>