V4L/DVB: ivtv: Timing tweaks and code re-order to try and improve stability

Added small delay on device open & close to allow hardware to settle. Move yuv
register restore to before the decoder firmware call to stop playback.

Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk>
Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>