V4L/DVB (8086): ivtv/cx18: fix video_temporal_filter handling

If the capture is scaled, then the video_temporal_filter is set to 0
by the cx2341x.c module since otherwise you would get ghosting.

However, this was also done in the VIDIOC_S_FMT ioctl which meant that
the video_temporal_filter control was reset to 0 or 8 each time S_FMT
was called. This was old code that should have been removed a long time
ago.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>