media: imx-mipi-csis: Initial support for multiple output channels

Some CSIS instances feature more than one output channel. Update
register macros accordingly, parse the number of channels from the
device tree, and update register dumps and event counters to log
per-channel data.

Support for routing virtual channels and data types to output channels
through the subdev internal routing API will come later.

Link: https://lore.kernel.org/r/20250822002734.23516-13-laurent.pinchart@ideasonboard.com


Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>