media: cedrus: set codec ops immediately

We'll need codec ops soon after output format is set in following
commits. Let's move current codec setup to set output format callback.
While at it, let's remove one level of indirection by changing
current_codec to point to codec ops structure directly.

Acked-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>