V4L/DVB (4983): Force temporal filter to 0 when scaling to prevent ghosting.

Change the code to unconditionally turn off the temporal filter when scaling.
If the window is not full screen the filter will introduce a nasty ghosting
effect.

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