media: cadence: csi2rx: Add link validation

Add media link validation to make sure incorrectly configured pipelines
are caught.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Tested-by: Julien Massot <julien.massot@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Jai Luthra <j-luthra@ti.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>