[media] V4L2: soc-camera: remove several CEU references in the generic scaler

The scaling / cropping library, that has been extracted from the CEU
driver still contained a couple of references to the original hardware.
Clean them up.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>