dt-bindings: clock: bcm63xx: add 6318 gated clock bindings

Add BCM6318 to the binding documentation for the gated clock controllers found
on BCM63xx SoCs.

Signed-off-by: Álvaro Fernández Rojas <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

Documentation/devicetree/bindings/clock/brcm,bcm63xx-clocks.txt

···
 Required properties:
 - compatible: must be one of:
 	 "brcm,bcm3368-clocks"
+	 "brcm,bcm6318-clocks"
+	 "brcm,bcm6318-ubus-clocks"
 	 "brcm,bcm6328-clocks"
 	 "brcm,bcm6358-clocks"
 	 "brcm,bcm6362-clocks"