[media] v4l: vsp1: Add HGO support

The HGO is a Histogram Generator One-Dimension. It computes per-channel
histograms over a configurable region of the image with optional
subsampling.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>