media: imx: imx7-media-csi: Don't set the buffer stride when disabling

There's no need to set the buffer stride to 0 when disabling the CSI.
Remove the extraneous register write.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>