dt-bindings: add device binding for the CCU of Allwinner V3s

Allwinner V3s is now driven by sunxi-ng CCU driver.

Add devicetree binding for it.
Signed-off-by: NIcenowy Zheng <icenowy@aosc.xyz>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

Documentation/devicetree/bindings/clock/sunxi-ccu.txt

@@ -7,6 +7,7 @@ Required properties :
 		- "allwinner,sun8i-a23-ccu"
 		- "allwinner,sun8i-a33-ccu"
 		- "allwinner,sun8i-h3-ccu"
+		- "allwinner,sun8i-v3s-ccu"
 		- "allwinner,sun50i-a64-ccu"
 
 - reg: Must contain the registers base address and length