HardwareSerial: change byte to uint8_t (since byte definition isn't present).

Author: damellis

hardware/arduino/cores/arduino/HardwareSerial.h

@@ -53,7 +53,7 @@ class HardwareSerial : public Stream
       volatile uint8_t *ucsrc, volatile uint8_t *udr,
       uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udrie, uint8_t u2x);
     void begin(unsigned long);
-    void begin(unsigned long, byte);
+    void begin(unsigned long, uint8_t);
     void end();
     virtual int available(void);
     virtual int peek(void);