media: vicodec: Disable (TRY_)DECODER_CMD for the stateless case

media: vicodec: Disable (TRY_)DECODER_CMD for the stateless case

The (TRY_)DECODER_CMD ioctls are only useful for stateful decoders and for
stateless decoders that support holding capture buffers (which is not the
case for this driver).

Disable them when registering the stateless decoder.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>