[media] v4l: vsp1: Support VSP1 instances without any UDS

Not all VSP1 instances include a UDS. Make the renesas,#uds DT property
optional and accept a number of UDS equal to 0 as valid.

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

Documentation/devicetree/bindings/media/renesas,vsp1.txt

@@ -13,12 +13,13 @@ Required properties:
   - clocks: A phandle + clock-specifier pair for the VSP1 functional clock.
 
   - renesas,#rpf: Number of Read Pixel Formatter (RPF) modules in the VSP1.
-  - renesas,#uds: Number of Up Down Scaler (UDS) modules in the VSP1.
   - renesas,#wpf: Number of Write Pixel Formatter (WPF) modules in the VSP1.
 
 
 Optional properties:
 
+  - renesas,#uds: Number of Up Down Scaler (UDS) modules in the VSP1. Defaults
+    to 0 if not present.
   - renesas,has-lif: Boolean, indicates that the LCD Interface (LIF) module is
     available.
   - renesas,has-lut: Boolean, indicates that the Look Up Table (LUT) module is

drivers/media/platform/vsp1/vsp1_drv.c

@@ -511,7 +511,7 @@ static int vsp1_parse_dt(struct vsp1_device *vsp1)
 		return -EINVAL;
 	}
 
-	if (pdata->uds_count <= 0 || pdata->uds_count > VSP1_MAX_UDS) {
+	if (pdata->uds_count > VSP1_MAX_UDS) {
 		dev_err(vsp1->dev, "invalid number of UDS (%u)\n",
 			pdata->uds_count);
 		return -EINVAL;