ARM: dts: st: Add gpio-ranges for stm32f746-pinctrl

Since commit 913a956c ("pinctrl: stm32: use dynamic allocation
of GPIO base"), it's impossible to retrieve gpios from phandle,
for example, mmc driver can't retrieve cd-gpios.
Add missing gpio-ranges properties to fix it.
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/st/stm32f746-pinctrl.dtsi

@@ -8,4 +8,48 @@
 
 &pinctrl {
 	compatible = "st,stm32f746-pinctrl";
+
+	gpioa: gpio@40020000 {
+		gpio-ranges = <&pinctrl 0 0 16>;
+	};
+
+	gpiob: gpio@40020400 {
+		gpio-ranges = <&pinctrl 0 16 16>;
+	};
+
+	gpioc: gpio@40020800 {
+		gpio-ranges = <&pinctrl 0 32 16>;
+	};
+
+	gpiod: gpio@40020c00 {
+		gpio-ranges = <&pinctrl 0 48 16>;
+	};
+
+	gpioe: gpio@40021000 {
+		gpio-ranges = <&pinctrl 0 64 16>;
+	};
+
+	gpiof: gpio@40021400 {
+		gpio-ranges = <&pinctrl 0 80 16>;
+	};
+
+	gpiog: gpio@40021800 {
+		gpio-ranges = <&pinctrl 0 96 16>;
+	};
+
+	gpioh: gpio@40021c00 {
+		gpio-ranges = <&pinctrl 0 112 16>;
+	};
+
+	gpioi: gpio@40022000 {
+		gpio-ranges = <&pinctrl 0 128 16>;
+	};
+
+	gpioj: gpio@40022400 {
+		gpio-ranges = <&pinctrl 0 144 16>;
+	};
+
+	gpiok: gpio@40022800 {
+		gpio-ranges = <&pinctrl 0 160 8>;
+	};
 };