media: sun6i-csi: Define and use driver name and (reworked) description

Add proper defines for driver name and description instead of
MODULE_NAME and hardcoding (cosmetics).

Also rework the description while at it to mention the hardware
generation that the driver supports and remove the video capture
mentions since it applies to the whole media device.

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>