Switch 'available' return type to uint8_t

This function never returns an error (-1), and the number of bytes available will never be a negative number.

Author: dmadison

cores/arduino/xinput/USB_XInput_API.cpp

@@ -34,7 +34,7 @@ boolean XInputUSB::connected() {
 	return USBDevice.configured();
 }
 
-int XInputUSB::available() {
+uint8_t XInputUSB::available() {
 	return USB_Available(XINPUT_RX_ENDPOINT);
 }
 

cores/arduino/xinput/USB_XInput_API.h

@@ -37,9 +37,9 @@ class XInputUSB {
 public:
 	// API
 	static bool connected(void);
-	static int  available(void);
-	static int  send(const void *buffer, uint8_t nbytes);
-	static int  recv(void *buffer, uint8_t nbytes);
+	static uint8_t available(void);
+	static int send(const void *buffer, uint8_t nbytes);
+	static int recv(void *buffer, uint8_t nbytes);
 	static void setRecvCallback(void(*callback)(void));
 
 	// Non-API Data