adjusted SERIAL_PORT* metadata in variant.h

variants/arduino_zero/variant.h

@@ -184,10 +184,10 @@ extern Uart Serial1;
 // 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_USBVIRTUAL      SerialUSB
-#define SERIAL_PORT_HARDWARE        Serial
-#define SERIAL_PORT_HARDWARE1       Serial1
-#define SERIAL_PORT_MONITOR         SERIAL_PORT_HARDWARE
-#define SERIAL_PORT_HARDWARE_OPEN   SERIAL_PORT_HARDWARE1
+#define SERIAL_PORT_MONITOR         Serial
+// Serial has no physical pins broken out, so it's not listed as HARDWARE port
+#define SERIAL_PORT_HARDWARE        Serial1
+#define SERIAL_PORT_HARDWARE_OPEN   Serial1
 
 #endif /* _VARIANT_ARDUINO_ZERO_ */