Fix SERIAL_* metadata in Arduino Ethernet variant

Author: cmaglie

hardware/arduino/variants/ethernet/pins_arduino.h

@@ -231,6 +231,6 @@ const uint8_t PROGMEM digital_pin_to_timer_PGM[] = {
 // SERIAL_PORT_HARDWARE_OPEN  Hardware serial ports which are open for use.  Their RX & TX
 //                            pins are NOT connected to anything by default.
 #define SERIAL_PORT_HARDWARE       Serial
-#define SERIAL_PORT_HARDWARE_OPEN  Serial1
+#define SERIAL_PORT_HARDWARE_OPEN  Serial
 
 #endif