arm: dts: dragonboard845c: add volume up

Add the volume up button as a GPIO button mapped to the up key.

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/arch/arm/dts/dragonboard845c.dts b/arch/arm/dts/dragonboard845c.dts
index 88247d7..db15e5d 100644
--- a/arch/arm/dts/dragonboard845c.dts
+++ b/arch/arm/dts/dragonboard845c.dts
@@ -59,6 +59,16 @@
 		enable-active-high;
 		states = <0 0>, <1800000 1>;
 	};
+
+	gpio-keys {
+		compatible = "gpio-keys";
+
+		key-vol-up {
+			label = "Volume Up";
+			linux,code = <KEY_UP>;
+			gpios = <&pm8998_gpios 5 GPIO_ACTIVE_LOW>;
+		};
+	};
 };
 
 &pm8998_resin {