V4L/DVB: Corrected CVBS input for the AVERMEDIA 777 DVB-T

The .vmux entry needs to be 1 instead of 0

Signed-off-by: Hartmut Hackmann <hartmut.hackmann@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>