pinctrl: mt65xx: add OF bindings for MT8516

Add binding documentation of pinctrl-mt65xx for MT8516 SoC.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/pinctrl-mt65xx.txt

@@ -11,6 +11,7 @@ Required properties:
 	"mediatek,mt8127-pinctrl", compatible with mt8127 pinctrl.
 	"mediatek,mt8135-pinctrl", compatible with mt8135 pinctrl.
 	"mediatek,mt8173-pinctrl", compatible with mt8173 pinctrl.
+	"mediatek,mt8516-pinctrl", compatible with mt8516 pinctrl.
 - pins-are-numbered: Specify the subnodes are using numbered pinmux to
   specify pins.
 - gpio-controller : Marks the device node as a gpio controller.