Adds support for cx25840 video decoder.

Driver authors: Hans Verkuil, Chris Kennedy, Tyler Trafford, Ulf Eklund.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Chris Kennedy <c@groovy.org>
Signed-off-by: Tyler Trafford <tatrafford@comcast.net>
Thanks-to: Ulf Eklund <ivtv@eklund.to>.
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>