media: coda: flag the last encoded buffer

Use the flagged last output buffer to also flag the corresponding
capture buffer after encoding. This causes the end of stream event
to be issued and the buffer to be dequeued with the last flag set.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>