media: camss: Add VFE files

These files control the VFE module. The VFE has different input
interfaces. The PIX input interface feeds the input data to an image
processing pipeline. Three RDI input interfaces bypass the image
processing pipeline. The VFE also contains the AXI bus interface which
writes the output data to memory.

RDI interfaces are supported in this version. PIX interface is not
supported.

Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>