V4L/DVB (5114): Cx88: Add support for svideo/composite input of the Terratec Cinergy 1400 DVB-T

Adds support for the combined S-Video/Composite input of the
Terratec Cinergy 1400 DVB-T.

Signed-off-by: Heiko Baums <heiko@baums-on-web.de>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>