media: sun8i-di: Fix power on/off sequences

According to user manual, reset line should be deasserted before clocks
are enabled. Also fix power down sequence to be reverse of that.

Fixes: a4260ea4 ("media: sun4i: Add H3 deinterlace driver")
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>