[media] media: mx2_camera: Don't modify non volatile parameters in try_fmt

Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
[g.liakhovetski@gmx.de: also don't clear pcdev->resizing in .try_fmt()]
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>