As the formats on the sink and source pad might be different store
them separately.

The pad format is used to configure the image width and height in
mipi_csis_system_enable(). As the csis cannot downscale, using the sink
or the source one isn't relevant.
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>