pinctrl: dt-binding: document berlin4ct SoC pinctrl

Add berlin4ct to existing berlin pinctrl device tree binding.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Acked-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: NAntoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/berlin,pinctrl.txt

@@ -20,7 +20,10 @@ Required properties:
 	"marvell,berlin2cd-soc-pinctrl",
 	"marvell,berlin2cd-system-pinctrl",
 	"marvell,berlin2q-soc-pinctrl",
-	"marvell,berlin2q-system-pinctrl"
+	"marvell,berlin2q-system-pinctrl",
+	"marvell,berlin4ct-avio-pinctrl",
+	"marvell,berlin4ct-soc-pinctrl",
+	"marvell,berlin4ct-system-pinctrl"
 
 Required subnode-properties:
 - groups: a list of strings describing the group names.