airoha/dts: use bootdelay=2 for evaluation boards.

It should be easy to enter u-boot command line for development only boards.

airoha/dts/en7523_evb.dts

@@ -14,6 +14,10 @@
 		compatible = "iopsys,tcledctrl_stub";
 		pon-tx-power-gpio = <&gpio0 16 GPIO_ACTIVE_LOW>;
 	};
+
+	config {
+		bootdelay = <2>;
+	};
 };
 
 &pon_phy {

airoha/dts/en7581_eagle.dts

@@ -16,8 +16,11 @@
 		bootargs = "console=ttyS0,115200n8 qdma_init=bb onu_type=72 serdes_ethernet=112 serdes_wifi1=01 serdes_wifi2=01 serdes_usb1=00 serdes_usb2=02 serdes_pon=00";
 		stdout-path = &uart1;
 	};
-};
 
+	config {
+		bootdelay = <2>;
+	};
+};
 
 &voip {
 	slic-power-mode = "none";

airoha/dts/en7581_evb.dts

@@ -11,6 +11,10 @@
 / {
 	model = "EN75xx GENERIC";
 	compatible = "econet,en7581-evb", "econet,en7581", "airoha,en7581";
+
+	config {
+		bootdelay = <2>;
+	};
 };
 
 &voip {

airoha/dts/en7581_kite.dts

@@ -16,8 +16,11 @@
 		bootargs = "console=ttyS0,115200n8 qdma_init=bb onu_type=72 serdes_ethernet=112 serdes_wifi1=001 serdes_wifi2=001 serdes_usb1=000 serdes_usb2=002 serdes_pon=000";
 		stdout-path = &uart1;
 	};
-};
 
+	config {
+		bootdelay = <2>;
+	};
+};
 
 &voip {
 	slic-power-mode = "none";