media: rcar-csi2: Cleanup subdevice in remove()

[ Upstream commit f6d64d0d ]

Cleanup the V4L2 subdevice in the driver's remove function to
ensure its async connection are freed, and guarantee in future that
the subdev active state is cleaned up.

Fixes: 769afd21 ("media: rcar-csi2: add Renesas R-Car MIPI CSI-2 receiver driver")
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20240617161135.130719-4-jacopo.mondi@ideasonboard.com


Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>