V4L/DVB (5614): M920x: Disable second adapter on LifeView TV Walker Twin

Disable second adapter on LifeView TV Walker Twin while it doesn't work 
properly.

Signed-off-by: Aapo Tahkola <aet@rasterburn.org>
Signed-off-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>