dt-bindings: Add binding docs for V3D.

This was missed in the upstreaming process.
Signed-off-by: NEric Anholt <eric@anholt.net>
Acked-by: NStephen Warren <swarren@wwwdotorg.org>

Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt

@@ -35,6 +35,12 @@ Optional properties for HDMI:
 		  as an interrupt/status bit in the HDMI controller
 		  itself).  See bindings/pinctrl/brcm,bcm2835-gpio.txt
 
+Required properties for V3D:
+- compatible:	Should be "brcm,bcm2835-v3d"
+- reg:		Physical base address and length of the V3D's registers
+- interrupts:	The interrupt number
+		  See bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt
+
 Example:
 pixelvalve@7e807000 {
 	compatible = "brcm,bcm2835-pixelvalve2";
@@ -60,6 +66,12 @@ hdmi: hdmi@7e902000 {
 	clock-names = "pixel", "hdmi";
 };
 
+v3d: v3d@7ec00000 {
+	compatible = "brcm,bcm2835-v3d";
+	reg = <0x7ec00000 0x1000>;
+	interrupts = <1 10>;
+};
+
 vc4: gpu {
 	compatible = "brcm,bcm2835-vc4";
 };