V4L/DVB (8079): ivtv: Convert to video_ioctl2.

Based on an initial conversion patch from Douglas Landgraf.

Signed-off-by: Douglas Schilling Landgraf <dougsland@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>