media: rcar-vin: Gen3 can not scale NV12

The VIN modules on Gen3 can not scale NV12, fail format validation if
the user tries. Currently no frames are produced if this is attempted.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/platform/renesas/rcar-vin/rcar-dma.c

@@ -1312,6 +1312,11 @@ static int rvin_mc_validate_format(struct rvin_dev *vin, struct v4l2_subdev *sd,
 	}
 
 	if (rvin_scaler_needed(vin)) {
+		/* Gen3 can't scale NV12 */
+		if (vin->info->model == RCAR_GEN3 &&
+		    vin->format.pixelformat == V4L2_PIX_FMT_NV12)
+			return -EPIPE;
+
 		if (!vin->scaler)
 			return -EPIPE;
 	} else {