media: coda: split decoder sequence initialization out of start decoding

The sequence initialization already has to happen during the
initialization phase, after headers have been queued on the OUTPUT
queue. This means that sequence initialization has to be queued as
a work item from QBUF on the OUTPUT queue. The internal framebuffer
setup should be done later during VIDIOC_REQBUFS() on the CAPTURE
queue.

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>