[media] coda: first step at error recovery

This implements a simple handler for the case where decode did not finish
sucessfully. This might be helpful during normal streaming, but for now it
only handles the case where the context would deadlock with userspace,
i.e. userspace issued DEC_CMD_STOP and waits for EOS, but after the failed
decode run we would hold the context and wait for userspace to queue more
buffers.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>