media: imx: csc/scaler: fix v4l2_ctrl_handler memory leak

[ Upstream commit 4797a3dd ]

Free the memory allocated in v4l2_ctrl_handler_init on release.

Fixes: a8ef0488 ("media: imx: add csc/scaler mem2mem device")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>