ARM: dts: exynos: Add pinctrl config for Midas keys

This pins are externally pulled up, and so we should explicitly
configure them to disable the SoC-internal pull-downs. Previously
we relied on the bootloader doing this in order to allow the buttons
to function properly.
Signed-off-by: Simon Shields <simon@lineageos.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

arch/arm/boot/dts/exynos4412-midas.dtsi

@@ -94,6 +94,8 @@ vcc18mhl: voltage-regulator-5 {
 
 	gpio-keys {
 		compatible = "gpio-keys";
+		pinctrl-names = "default";
+		pinctrl-0 = <&gpio_keys>;
 
 		key-down {
 			gpios = <&gpx3 3 GPIO_ACTIVE_LOW>;
@@ -1009,6 +1011,11 @@ &pinctrl_1 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&sleep1>;
 
+	gpio_keys: gpio-keys {
+		samsung,pins = "gpx0-1", "gpx2-2", "gpx2-7", "gpx3-3";
+		samsung,pin-pud = <EXYNOS_PIN_PULL_NONE>;
+	};
+
 	max77693_irq: max77693-irq {
 		samsung,pins = "gpx1-5";
 		samsung,pin-pud = <EXYNOS_PIN_PULL_NONE>;