media: amphion: handle firmware debug message

decoder firmware may notify host some debug message,
it can help analyze the state of the firmware in case of error

Fixes: 9f599f35

 ("media: amphion: add vpu core driver")
Signed-off-by: Ming Qian <ming.qian@nxp.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>