media: cedrus: Add support for R40

Video engine in R40 is very similar to that in A33 but it runs on lower
speed, at least according to OS images released by board designer.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>