V4L/DVB (6116): ivtv: VBI cleanups and fixes

Besides some VBI cleanups this patch also fixes a subtle problem with the
VBI re-insertion stream where the PIO work handler wasn't called quickly
enough, resulting in occasional corrupt data.

Furthermore the CC output didn't disable CC correctly and at the right time,
causing duplicates to be sent.

An saa7127 fix for VPS output was also added: the wrong data was sent.

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