dt-bindings: cp110: document the new CP115 pinctrl compatible

A new compatible is going to be used for Armada CP115 pinctrl block,
document it.
Signed-off-by: Grzegorz Jaszczyk <jaz@semihalf.com>
[<miquel.raynal@bootlin.com>: split the documentation out of the
driver commit]
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20190805101607.29811-3-miquel.raynal@bootlin.comReviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/arm/marvell/cp110-system-controller.txt

@@ -78,8 +78,8 @@ Documentation/devicetree/bindings/pinctrl/marvell,mvebu-pinctrl.txt.
 
 Required properties:
 
-- compatible: "marvell,armada-7k-pinctrl",
-  "marvell,armada-8k-cpm-pinctrl" or "marvell,armada-8k-cps-pinctrl"
+- compatible: "marvell,armada-7k-pinctrl", "marvell,armada-8k-cpm-pinctrl",
+  "marvell,armada-8k-cps-pinctrl" or "marvell,cp115-standalone-pinctrl"
   depending on the specific variant of the SoC being used.
 
 Available mpp pins/groups and functions: