ARM: dts: zynq: Use gpio constants for the Zybo Z7 board

Include GPIO dt-bindings and use GPIO_ACTIVE_* constants
to improve readability
Signed-off-by: Luis Araneda <luaraneda@gmail.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/boot/dts/zynq-zybo-z7.dts

 // SPDX-License-Identifier: GPL-2.0+
 /dts-v1/;
 #include "zynq-7000.dtsi"
+#include <dt-bindings/gpio/gpio.h>
 
 / {
 	model = "Digilent Zybo Z7 board";
@@ -24,7 +25,7 @@ chosen {
 	usb_phy0: phy0 {
 		#phy-cells = <0>;
 		compatible = "usb-nop-xceiv";
-		reset-gpios = <&gpio0 46 1>;
+		reset-gpios = <&gpio0 46 GPIO_ACTIVE_LOW>;
 	};
 };