media: imx: fix a potential memory leak in imx_media_csc_scaler_device_init()

Add video_device_release() in label 'err_m2m' to release the memory
allocated by video_device_alloc() and prevent potential memory leaks.
Remove the reduntant code in label 'err_m2m'.

Fixes: a8ef0488 ("media: imx: add csc/scaler mem2mem device")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>