media: amphion: support to decode sorenson spark video

Sorenson Spark is an implementation of H.263 for use
in Flash Video and Adobe Flash files.
amphion decoder can support it by insert some startcode
before sequence and picture.

Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>