media: sun6i-csi: Pass and store csi device directly in video code

The video structure is part of the main csi device structure, so pass
pointers to that top-level structure directly. This makes it easier to
navigate and access other elements. No functional change intended.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>