media: amphion: Reduce decoding latency for HEVC decoder

The amphion decoder firmware supports a low latency flush mode for the
HEVC format since v1.9.0. This feature, which is enabled when the
display delay is set to 0, can help to reduce the decoding latency by
appending some padding data to every frame.

Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>