[media] media: coda: ignore coda busy status in coda_job_ready

job_ready is supposed to signal whether a context is ready to be
added to the job queue, not whether the CODA is ready to run it
immediately.
Calling v4l2_m2m_job_finish at the end of coda_irq_handler already
guarantees that the coda is ready when v4l2-mem2mem eventually tries
to run the next queued job.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>