media: imx-jpeg: Fix occasional decoder fail on jpegs without DHT

Add some body to the dummy jpeg used to inject a default DHT.
Use jpeg_image_red as compressed image data, insert it at the
end of SOS, before EOI.

The pure dummy jpeg was occasionally not working well on
8qxp C0.

Signed-off-by: Mirela Rabulea <mirela.rabulea@nxp.com>
Reviewed-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>