media: imx-jpeg: Propagate the output frame size to the capture side

The GStreamer v4l2videodec only ever calls S_FMT on the output side
and then expects G_FMT on the capture side to return a valid format.

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